Set 30 years in the future, colonization in space is now a reality, and the Robinson family is among those tested and selected to make a new life for themselves in a better world. But when the new colonists are abruptly torn off course en route to their new home, they must forge new alliances and work together to survive in a dangerous alien environment, lightyears from their original destination.
The Robinsons start to adjust to life on a new planet following their crash landing, but unbeknownst to them, they’re not the only colonists to have survived. A terrifying storm threatens everyone’s safety.
When the Robinsons discover that the Jupiter 2 has a major fuel leak, they must act quickly to free the ship with any remaining power before the glacier collapses around them. Light is shed on Dr. Smith’s mysterious past.
John and Maureen make a surprising discovery, explaining why they haven’t been able to make contact with the Resolute. Judy learns the truth about the Robot's mysterious past and forces Will to make a difficult decision. Meanwhile, Dr. Smith is ready to launch a plan of her own.
The survivors work together to build a massive light tower to send a signal to the Resolute, but the Robot is noticeably absent from the group. Dr. Smith’s plan takes shape as she feels her time on the lost planet is running out. Maureen makes a daring discovery.
Not wanting to panic the others, John and Maureen quietly grapple with her discovery, but Penny overhears their conversation and is anxious to share her secret. Will learns a valuable lesson as he takes responsibility for the Robot’s actions, and Judy (accompanies Don on a critical search for fuel that turns treacherous. Dr. Smith manipulates a vulnerable situation into one that could prove deadly.
While Dr. Smith moves ahead with his secret project, seismic activity wreaks havoc across the planet and leaves two teams facing impossible choices.
Just as Maureen and John start to rebuild their relationship, the Robinsons are pulled apart again when John volunteers to undertake a risky mission. Tensions run high as family members do their best to prepare him – everything comes down to this moment, their only chance at survival. But Dr. Smith has another plan that tests even her manipulation skills.
The Robinson children are forced to come to terms with the fates of their father and Don. Will and Penny seek out an unconventional energy alternative that could power the remaining Jupiters to launch into space, and Judy sets out to find Maureen who has been taken captive by Smith. But Smith won’t let her go easily.
The Robinson family scrambles to launch their Jupiter from the Lost Planet, stage an impossible rescue, and reach the Resolute before it leaves orbit for good. Unfortunately, Dr. Smith and the Robot have other plans.