Gwen is shocked into drastic action when her father refuses to sign her application to finishing school. Darrell and Felicity fall out during the North Tower Spelling Bee.
Clarissa challenges her brother's team, Thackerton Boys, to a lacrosse match after he insults her playing skills. Mr Parker worries about Nancy when she is put in goal.
Gwen plots for movie star and Miss Grayling’s estranged cousin Lily Vernon to visit the school. Lily has her own secrets. Nancy plans a prank to stop eating carrots.
Bill is shocked when Thunder is put up for sale, and she desperately tries to keep him. The Third Formers prank Miss Vernon so they can get out of class to go for a swim.
Jean reveals uncomfortable truths about the Grayling family which shock Lily. Darrell and Alicia plan the best prank ever, involving ancient curses and a skeleton.
Lily discovers a hidden secret when she and Jo make a film. Miss Grayling is angry with Lily, who decides to leave - but has she gone for good?
Felicity and June follow a mysterious girl in uniform to Miss Grayling’s study, but she runs off. Miss Grayling checks her room, which appears in order - what did the intruder want?
Jo discovers Lily Vernon hiding out in the abandoned cottage and agrees to help her in secret, while Alicia decides Darrell needs to relax and plans their final midnight feast.
Gwen is furious with her father when he puts her future plans in doubt, but she is shocked when she finds out the truth. Jo believes Malory Towers now belongs to Lily.
Darrell is shocked to discover Lily’s plans and needs to act before Malory Towers is lost forever, while Gwen finds out Ron is joining the army and has to consider her own future.