Jack thinks he's identified the mole inside CTU. Kim and Janet realize they are being kidnapped and try to escape. Palmer orders an employee to get dirt on a reporter who might jeopardize his campaign. Ira Gaines' plans come to a halt when he must renegotiate with a conspirator.
District Director George Mason (Berkely) shuts down CTU forcing Jack to escape in order to follow up on a lead on a conspirator. Nina and Jamie try to cover for him. Palmer discovers how a reporter found out about Keith. Jack finally learns that Kim and Janet haven been kidnapped.
Jack follows the arrested conspirator to the police station in order to get more info on Kim's whereabouts. Palmer meets with a reporter who has some damaging information. Kim realizes just how dangerous Ira Gaines really is.
Jack meets up with Teri at the hospital where they wait to talk to Janet about Kim. However, Janet is killed by Alan who is really working for Ira Gaines. Palmer confronts his family about the cover up. The body of the real Alan York is found near CTU by Nina Meyers.
Jack is taken into custody by the Secret Service after he stops the assassination. He quickly escapes in order to check on another name from the key card. Palmer tries to deal with the assassination attempt.
Jack is on the run after escaping custody and rushes to intercept Ted Cofell before he leaves the city. Nina receives a phone call from Teri and tries to trace the call. Palmer still wants to go ahead with the press conference despite objections. Alberta Green temporarily takes over as Director of CTU.
Jack takes Ted Cofell hostage after finding his name on the key-card and tries to get whatever info he has about the conspiracy which only amounts to the name of another conspirator, a one Kevin Carroll. Palmer starts to piece together his connection to Jack. Gaines receives orders to kill Teri and Kim from his boss Andre Drazen.
Kevin Carroll (the man who pretended to be York) leads Jack to Gaines' compound where he is quickly discovered. Nina and Tony try work around Director's Green's strict new protocols to help Jack. Palmer discovers that Carl Webb, one of his financiers is handling the Keith situation his own way.
Jack has a final confrontation with Gaines as a CTU chopper heads to the compound. Nina and Tony talk to Jamey's mother in order to learn why she was helping the assassins. Carl Webb threatens Palmer to keep quiet about the murder once and for all. CTU learns that more assassins are on their way to LA.
Director Green and Regional Director Ryan Chappelle question Jack about the day's events. Nina takes Kim and Teri to a safe house after getting them medical attention. Palmer wants a meeting with Jack.
After handing out photos of all the assassins, Jack and Mason discover that one of Palmer's campaign staff is in a romantic relationship with Alexis Drazen. Teri and Kim are attacked in the safehouse. Keith confronts Carl Webb about the cover-up.
Jack and Mason use Palmer's campaign staffer Elizabeth Nash in a sting against Alexis Drazen which backfires badly on them. Kim makes a run for Rick's house after getting separated from Teri following the attack.
Jack poses as Alexis Drazen and goes to meet a contact who has vital information. However, a CTU agent with a grudge against Jack might risk the success of the mission. Dr. Parslow takes Teri back to the Bauer house.
Jack and Mason search for location of the address found in Victor Drazen's confidential file. Palmer finally lets the press know about Keith's past. One of Drazen's goons closes in on Teri; Kim is arrested after the police raid Rick's house.
In order to buy himself more time Jack puts Victor and Andre in contact via Mason with a hospitalized Alexis Drazen. Palmer becomes involved with a campaign staffer. Tony and Nina learn that Kim has been recaptured.
Jack goes undercover to find Joseph Wald, where he learns that CTU is going to be bombed. While Kim tries to save Meghan from her abusive father, Gary. Kate Warner becomes suspicious of sister's Middle-Eastern fiancé.
CTU is attacked and faces serious casualties. Jack discovers who gave Joseph Wald the schematics for CTU. President Palmer fires Rayburn after Kresge tells him about the 30-minute gap between Jack's warning and the bomb explosion.
Jack boards a plane with Nina Meyers and several FBI agents because they have to meet a contact in Visalia,California who has info on the bomb's location. Nina tries to escape after meeting the contact. President Palmer and Mike Novick try to ascertain NSA Director Stanton's loyalty. Mason tries to make contact with his estranged son. Tony takes Bob Warner and Reza to CTU for further questioning.
Jack and Nina try to get more information out of her contact on the way back to LA. Tony learns of Bob Warner's status as a CIA contractor. Stanton expresses concerns about Sherry's presence as she tries to make a deal with a detained reporter.
The plane carrying Jack and Nina is shot down and together they must fight off a group of soldiers. Mason plays Bob Warner against Reza to find out which one working with the terrorists. Kate Warner is captured and interrogated by Syed Ali. Mason reveals the truth of his condition to Tony.
Jack is captured by Nina Meyers and used as leverage in an attempt to get a presidential pardon. President Palmer learns the identity of one of the conspirators in his administration. After being set free, Reza learns the identity of the person who set him up when he goes to get incriminating evidence on Bob. Jack begins to suspect the soldiers who shot him down were with the NSA as he heads to capture Syed Ali.
Kate Warner leads Jack on mission to locate and id Syed Ali. President Palmer places Stanton under arrest and makes an out of character decision on how to handle the interrogation. CTU discovers that Marie killed Reza and the two agents trailing him.
Jack tries to get information out of Syed Ali. Mason gets Bob Warner to reveal some previously classified history on Marie that paints Reza's murder in a new light. Lynne Kresge becomes suspicious of Sherry.
Jack searches for the secondary team of Coral Snake Commandos as a Tactical Team gets closer to the bomb's location. Division sends in Brad Hammond to look into CTU LA's situation. Stanton finally reveals that he's known about the bomb all along and allowed it to be smuggled into the country.
Jack gets back to CTU after the bomb exploded. The situation there is tense since Tony became head of the Unit, especially when a key witness is assassinated. President Palmer and his staff prepare a retaliation on the three countries involved with Ali.
Jack and Kate leave CTU to meet with the lone surviving member of the Coral Snake Commandos who says he has evidence that the tape is fake. President Palmer wants to wait and see what Jack finds out before launching a retaliatory strike.
Jack, Kate, and Yousef try to get Wallace to a hospital after he gets shot by unknown assailants. President Palmer tries to deal with civil unrest as Muslim communities across the country are targeted.
Jack is captured by a group of men working for an oil magnate named Peter Kingsley who's looking to capitalize on the coming war. Lynne Kresge discovers that Vice-President Prescott is planning on seizing the presidency by way of the 25th Amendment. President Palmer deals with some increasingly impatient Joint Chiefs of Staff. Kate and Yusef are attacked by angry American citizens when they try to get the chip behind the Ali recording back to CTU.
Jack tries to escape from the Kingsley's men after being tortured. Lynn Kresge tries to warn President Palmer about VP Prescott. Regional Director Ryan Chappelle returns to CTU and exerts his authority. Kate tries to retrieve the stolen computer chip. President Palmer begins to suspect something is wrong when Prescott won't return his phone calls.
After saving Kate from her attackers Jack heads to meet Alex Hewitt who may be the person who designed the computer chip. President Palmer's ability to the run the country is questioned when the Vice-President and members of the cabinet invoke the 25th Amendment.
Jack has Sherry contact Peter Kingsley who turns out to be the mastermind behind the tape. Mike Novick realizes that he has made a huge error in judgment in supporting Prescott. Deputy Regional Director Brad Hammond places Tony and Michelle under arrest.
Jack and Sherry Head to L.A. Collesium to meet Peter Kingsley. VP Prescott calls off the airstrike to see what comes out of the meeting. After being restored to power President Palmer speaks to the nation about the nuclear bomb.
Three years later; CTU receives a threat that Mexican drug lord Hector Salazar is planning on releasing a deadly contagious virus in LA unless Jack gets his brother Ramone Salazar out of prison. President Palmer prepares for a presidential debate with Senator John Keeler.
After Goss' infected body is dropped at the hospital Jack and Chase begin to trace his last known locations while CTU tries to figure out how the virus is gonna be unleashed to the public at large. Once they figure out it's gonna be spread through cocaine shipments CTU begins to track down drug dealers in East LA. President Palmer considers canceling the debate.
Tony and one of Salazar's cronies close in on a young drug trafficker who may be unknowingly carrying the virus. Jack informs Kyle Singer's parents that he may be infected. Wayne becomes concerned over David's latest affair when he learns the woman's ex-husband will perjure himself over sworn testimony he gave years earlier unless the President pays him not to.
In order to get Ramon out of prison Jack asks for President Palmer's permission to instigate a prison riot. Michelle takes over command of CTU after Tony is injured. Chase disobeys orders and fiercely interrogates Roman as Jack puts his plan into motion. President Palmer has Wayne call off the meeting with Anne's ex-husband. Drug dealer Kyle Singer is captured by Salazar's men.
Jack and Ramon are captured by dangerous prison inmates after trying to escape. President Palmer begins his debate with Senator Keeler. At CTU, Chloe O'Brian discovers evidence of Jack's heroin addiction.
Jack and Ramon try evade military helicopters when they make a run for a plane scheduled to leave for Mexico. Palmer cancels the debate. Kyle Singer learns that he is not infected with the virus. Kim discovers that Gael Ortega might be working with the Salazars.
Ramon holds Jack hostage as they fly down to Mexico. Regional Director Chappelle interrogates Gael; Tony returns prematurely to CTU to reveal Gael's true allegiance. Chase disobeys orders and heads for Mexico to rescue Jack.
A snag in the sale of the virus leads the Salazars to question Jack's motivations and as a result they put his allegiances to the test. Claudia works to help Chase escape after Jack informs her of his real priorities. Tony's ability to run CTU is called into question. Palmer is put into a difficult position regarding his brother.
In order to get closer to the virus, Jack tries to make Nina believe he still has feelings for her. Wayne tries to gain the trust of Julia Milliken when Alan Milliken starts making demands. Chase convinces Salazar's girlfriend to help him escape.
Jack and Nina prepare to meet with Amador, the man selling the virus; CTU organizes an ambush. Ramon and Hector have a falling out. President Palmer asks his ex wife Sherry to help with the Milliken situation.
Nina releases a deadly computer virus into CTU's systems after getting captured by Jack and Chase. Sherry runs out of options and decides to directly confront Alan Milliken but things go too far. Chloe and the rest of the tech crew work overtime to combat the virus.
Regional Director Chappelle forces Jack to undergo a medical evaluation for his heroin addiction. Tony interrogates Nina Meyers. Julia Milliken confronts Sherry after Alan dies while Wayne and President Palmer prepare for the fallout. Nina tries to escape custody after collapsing during the interrogation.
Amador and his people receive orders from their client to release the virus in the Chandler Plaza Hotel. Jack closes in on Amador but it's too late. Michelle and Gael alert the Chandler's Chief of Security to the dangers of the threat.
After the interrogation goes nowhere, Jack and Chase let Amador escape hoping he will lead them to his client's location. Michelle places the hotel under quarantine and must make a difficult decision in how to handle the ensuing panic. President Palmer is put into a awkward position when handling the Milliken situation.
President Palmer gives into Stephen Saunders's strange demand of placing an seemingly nondescript phrase into a speech in the hopes of delaying another viral outbreak. Michelle takes control of the situation inside the hotel. Jack and Chase bring a suspect to the local branch of MI-6 as Saunders launches an attack on the building.
Jack has to comply with another one of Saunders' demands: the death of Regional Director Ryan Chappelle. Michelle discovers that one of the infected hotel patrons got out before the quarantine was enforced.
When CTU learns that Saunders has a daughter attending an LA university they must inform Jack the only match for a bait and switch operation is Kim Bauer. Chase tracks down the man who escaped the hotel quarantine. Palmer informs his cabinet on the dangers of the threat.
Jack works on using Saunders' daughter in an attempt to gain control of the virus. Michelle waits to find out if she's infected. Palmer navigates around a angry and confused press. Saunders starts making demands on Tony.
Tony works covertly to find a way to get Janes Saunders out of CTU and deliver her to Saunders before Jack and Chase find him. Senator Keeler receives some damaging information on President Palmer from a surprising source.
Jack and Tony clash as they wait for the time of hostage exchange with Saunders. Senator Keeler confronts President Palmer about the Milliken cover-up while Wayne initiates a secret operation against Sherry.
Jack and Chase corner Saunders' henchman Arthur Rabens in an active public school. Tony faces losing command of CTU and treason charges for saving Michelle. An emotionally broken President Palmer decides to drop out of the race for reelection.
Jack creates a faux-hostage crisis in a convenience store trapping Kalil and several innocent bystanders to buy Chloe more time to get the surveillance satellite working properly. Dina's murders Behrooz's girlfriend after she becomes suspicious. Audrey and Secretary Heller try to escape.
Jack and Director Driscoll agree to a truce and work together after the police make a mistake in handling the Kalil situation which means that Jack also has to find a new lead. The terrorist begin to threaten Audrey unless Heller confesses to “war crimes” on camera in an hour.
Jack initiates a fierce gun battle with the terrorists as he races to rescue Audrey and Secretary Heller before the military strikes. Dina is shocked to learn that Navi and Marwan plan to have Behrooz killed. Secretary Heller learns his son is a suspect and allows the interrogation to continue. Curtis Manning learns that the briefcase stolen from the train bombing contains a Dobson Override that could potentially give terrorists control of America's 104 nuclear plants.
Jack takes Audrey into the field in order to ID a suspect she recognized from the compound, but the terrorists learn where they are and pin them down. Jack calls on an old friend to escape. Dina tries to get to Behrooz before Navi does. Edgar Stiles works overtime to get back control of 87 to 98 nuclear plants by taking their systems off-line before the Override gets to them.
Jack and Audrey hide out with Tony Almeida after escaping from the terrorists and learn the man they are looking for is an employee for McClennan-Forrester. Behrooz takes Dina to the hospital to get medical attention. President Keeler orders six cities to be evacuated. Secretary Heller tries to flush out the mole in CTU, but the evidence points in the wrong direction.
Jack and Tony stumble on to Dina and Behrooz's trail after a key suspect has been assassinated. Edgar tries all he can to get his mother out of the fallout zone of the San Gabriel Island nuclear power station. Driscoll and Curtis cover their tracks following the revelation about Marianne. Navi closes in on Behrooz when he tries to get medication for Dina.
Jack races to save Behrooz from his father when the situation turns into a hostage crisis. Dina points Jack and Tony to a safe-house where they find evidence that points to Paul Raines' involvement with the terrorists. Marianne leads Curtis to a computer that contains info on the terrorists, but Curtis feels like it could be a trap.
After finding out that Audrey's husband, Paul Raines, may have information about the override, Jack decides it's time for some “shock treatment”. The lead that Curtis was following up on at the Rockland Building proves to be vital, just as the remaining 5 nuclear reactors prepare to meltdown. Meanwhile, Tony does some interrogating of his own, and Driscoll deals with devastating news.
Jack and Paul Raines visit the corporate headquarters of McLennan-Forster, the defense contractor that employed Marwan. The company executives activate an EMP bomb to destroy incriminating evidence in order to protect themselves. Tony is given temporary command of CTU after Driscol resigns following her daughter's suicide.
Jack and Paul enlist civilian help when they must fend off mercenaries from McLennan-Forster. Tony discovers that Michelle is taking over command of CTU. Marwan orders an underling to kill an Air Force pilot and his family and assume the pilot's identity.
Jack and Dina's attempt to infiltrate one of Marwan's terrorist cells backfires on them. Michelle orders Chloe back to work when Edgar begins to crack due to emotional pressure. Paul is taken into surgery after getting shot. Anderson gains access to an airfield and gets closer to the stealth bomber.
In order to buy more time for Anderson to close in on Air Force One, Marwan calls CTU and tells Michelle that he is willing to trade Jack for Behrooz. Bill Buchanan arrives at CTU and assumes command. Curtis interrogates Behrooz for more information on Marwan.
CTU raids Marwan's headquarters but somehow allows Marwan to slip through their fingers during the confusion. Jack learns that the trade-off was nothing more than another ruse. Jack tries to talk Anderson out of the mission, but it's too little too late as far Anderson is concerned.
Jack's only hope of keeping the President's nuclear football (a computer containing the codes of America's nuclear facilities) out of Marwan's hands lies in two innocent campers who witnessed the crash of Air Force One. Mike Novick wants to immediately have Presidential authority shifted over to Vice President Charles Logan.
Jack discovers that Marwan's new objective is to find and activate a nuclear warhead after he realizes pages from “the football” are missing. Logan's presidency is not off to a good start when he starts showing signs of fear. CTU sends Curtis to intercept one of Marwan's subordinates but a lawyer from Amnesty Global stalls the interrogation.
Chloe is sent into the field for the first time to look into the report of a woman who claims her boyfriend is part of the conspiracy. Mike Novick calls in Former President David Palmer to assist President Logan. Jack's methods are questioned.
Palmer authorizes a extraction mission on the Chinese Embassy in LA to be lead by Jack and Curtis. The intended target is injured during the raid and the Chinese Consul is shot in friendly fire by his own people. Jack forces the doctors to stop working on Paul and help the suspect.
Jack fails to stop Marwan from launching the nuclear warhead. Richard Heller becomes a suspect again and James Heller leads the interrogation. Mandy takes Tony hostage after he checks up on Richard's information.
The Chinese representative kidnaps CTU Agent Howard Bern in an attempt to learn who lead the raid on the embassy. Palmer and Logan may have to evacuate major U.S. cities in the hopes of preventing nuclear disaster. Michelle tries to save Tony.
President Logan reinstates Jack to CTU when he learns that the US(not Russia) is in danger. Jack captures and must negotiate with a scientist who helped Bierko open the nerve gas canisters. President Logan must decide how to handle revealing Walt's complicity to the public.
Bierko contacts President Logan and demands information about the route of President Suvarov's motorcade. Jack races to protect a witness who helped supply Bierko the nerve gas cannisters before Bierko has him killed.
Homeland Security takes control of CTU. President Logan orders martial law. Wayne Palmer goes to meet with Aaron Pierce. Jack interferes with a German spy's undercover operation while searching for Bierko.
CTU makes Christopher Henderson their priority while dealing with the restructuring into Homeland Security. Jack and Wayne must save Evelyn Martin's daughter in order to get crucial information about the conspiracy.
Jack and Wayne must retrieve a digital recording from a safe deposit box before Henderson's men get to it. President Logan starts to cover his tracks when he orders Homeland Security to issue an arrest warrant for Jack.
Jack and Audrey show Secretary Heller the recording but are shocked by the actions he decides to take in handling it. Karen Hayes works to cut off Jack's support inside CTU. Mike Novick begins to become suspicious of President Logan's actions.
Jack and Buchanan work outside the chain of command by recruiting Curtis for help. Homeland Director, Karen Hayes, begins to see discrepancies in the President's actions and begins to suspect his motives.
When President Logan realizes that he's been backed into a corner, he resorts to a drastic solution. While Karen becomes an ally in Jack's quest to expose Logan, Miles changes allegiances, and a villain from the past returns.
Vladimir Bierko manages to escape custody and take control of a submarine, the Natalia, bent on getting his revenge against the US. Jack reluctantly teams up with Henderson in hopes of getting a lead on Bierko, while Martha helps Aaron.
The President meets with Jonas Hodges while Jack battles toxins in his body and works with someone inside the Starkwood compound: can they destroy the bio-weapons before rockets rain death on U.S. cities?
As dawn breaks over New York, President Taylor endures a game-changing setback as the threat of mass destruction looms. Meanwhile, President Hassan makes a shocking decision that surprises his loved ones. But before long, trusted confidantes will become enemies of the state, and it's only the beginning of the betrayals that are to come as the race against time ticks on.
President Taylor's envoy to the Russians persuades them to return to the peace table, but at what cost? Jack goes to CTU to interrogate a nearly-forgotten traitor, and the President decides to talk to Jack there.
President Allison Taylor faces impossible choices and much to the dismay of CTU, she enlists a private security firm to complete a sensitive task led by Mark Bledsoe. Meanwhile, Jack calls in a favor to his old friend Rick Vickers before he embarks upon a crucial mission of his own.
While the media interview the peace delegates, Jack and Cole have gone rogue to rescue a traitor being tortured by off-the-grid operatives; Logan gets President Taylor to approve putting his aide in charge of the manhunt.
While delegates review the peace agreement, Jack searches for evidence of Russian involvement in the day's tragedies, covered up at the highest levels. Ex-President Logan is desperate to neutralize Jack.
Jack's rogue operation includes kidnapping a high-profile target; pools of blood, a knife wound, and Chloe's mistrust of her new supervisor add texture while President Taylor feels the loneliness of power.
After four years off the grid, Jack is apprehended in London by the CIA – on the very day that President James Heller arrives. As the President faces political pressure over a US drone program run from a UK-based base, only disgraced agent Kate Morgan suspects that Jack's capture was all too easy.
The terror threat escalates as Jack heads for the U.S. Embassy with the CIA closing in on him. Meanwhile, Margot asserts her authority with unthinkable force; President Heller makes an impassioned speech to Parliament; and Kate takes matters into her own hands.
As the smoke clears after the devastating events of the first five hours, tensions between President Heller and Prime Minister Davies boil over, and one of them decides to take matters into his own hands. In the meantime, Jack proposes a plan to locate Margot by using someone unexpected as his unsuspecting bait. Back at the CIA in London, Jordan raises suspicions about Kate's husband.
Jack Bauer and President Heller endure the unthinkable to thwart the terror attacks of mastermind Margot Al-Harazi. Meanwhile, CIA agent Jordan Reed faces a life-or-death struggle and Kate takes drastic measures to track down Margot before it's too late.