In the first episode of a new series, the family are surprised to find out that Leslie has three different girlfriends, so Louisa decides to take it upon herself to help him pick one by having each member of the family invite their favourite girl to afternoon tea. Larry injures his leg and Theo decides to use his newly set-up x-ray unit to try and examine it. Elsewhere, Gerry continues to grow his animal collection, Margo takes up a job as Theo's assistant, and Aunt Hermione arrives in Corfu for good.
Louisa and Larry receive the devastating news that Aunt Hermione has died in her sleep. As the family make arrangements to have her body sent back to England, Margo gets to work on organizing a memorial service. Leslie decides that he wants to be with Dionisia, and prepares to let Daphne down gently - however, it turns out that she is pregnant with his child, and her father is determined that they must get married as soon as possible. Gerry becomes fascinated by a wall in the back garden that is covered in insects.
After arriving in Bournemouth at Aunt Hermione's house, Larry quickly sets off to visit friends in London. Louisa is left with her cousins Prue, Geoffrey and Basil who arrive to settle details of Hermione's will and attend the funeral.In London, Larry is greeted at his friend Durant's house by a group of like-minded artists – Henry Miller, Jonquil and Ruby – and begins to embrace their modern, bohemian lifestyle. Back in Corfu, Leslie takes charge of the household and is offered a job as a local policeman, whilst Spiros forbids Margo from seeing Zoltan in Louisa's absence and Gerry saves a donkey from an abusive farmer.
The family receives a telegram from Larry, who is in Athens for a short trip, announcing that he has a friend coming to stay – Prince Jeejeebuoy. Concerned about Gerry's education, Louisa also seeks advice from Theo.
Spiros spends time with a glamorous Italian family who have recently arrived on the island. Louisa is jealous of the attention he is paying their new neighbors and invites the new neighbors over to learn more about them. She ends up convinced they are hiding something, while Margo feels threatened by their eldest daughter. Larry joins the fire service, and Gerry falls in love.
The family plan a party to celebrate Gerry’s 13th birthday, but when a plague of mosquitoes descends, they are forced to hold it inside. As the party planning progresses, Louisa is finding it hard to accept that her youngest is growing up. Gerry insists that he doesn’t want a fuss, but gets frustrated and upset when the party is clearly aimed at someone much younger. Trying to pick up the mood, Margo’s transformation of an otherwise disastrous party results in hilarious antics as everyone but Spiros seems to join the party spirit. His distant behaviour concerns Louisa who wonders why he has locked himself in a room to sing sad love songs.
Louisa finds it more than a little awkward when Larry invites Henry Miller to stay. Insisting on walking around naked, the liberal contents of Henry's novels raise heated discussions within the family.
Meanwhile, with the Greek government clamping down on ‘immoral behaviour', Sven is arrested due to his sexuality. Larry is incensed and demands Margo obtain books on miscarriages of justice and fighting fascism from the Countess. However, learning that she is not permitting anyone to enter her villa, Larry takes matters into his own hands.
The family meets members of a travelling circus, and gets involved in helping them to drum up business. Larry falls in love with a contortionist, while Margo takes to the ring in person to perform a very dangerous act. Gerry is more concerned with making sure all of the animals featured in the show are well-treated. Spiros cannot bring himself to return to his empty house and begins spending more and more time at the Durrells' home - but the magic of the circus brings him and Louisa closer together. Last in the series.