Darrell’s final year starts with a fierce argument with Gwen, but she knows they need to work together. French student Celeste joins the Third and plays a prank on the teachers.

Alicia falls out with Darrell and the other sixth formers when she edits the school newsletter. Jo and Susan get into trouble with Mr Parker over his new typewriter.

The girls try to cheer up Celeste, who wants to get expelled so she can go home to see her mother. Mary-Lou finds herself facing a snail invasion when she takes an art class.

Irene offers to help Ron with his band, who are playing that afternoon, forgetting she has to take an important music exam. Felicity and June find clues to the missing time capsule.

Angry about not receiving a present from Paris, Celeste hides in the stables. However, she is trapped there with Matron when the stables catch fire.

Celeste lies that she started the fire on purpose to be sent home. Sally confronts Matron about her eyesight, and Miss Grayling finally tells Celeste the truth about her mother.