The girls welcome Bill and her horse Thunder to Malory Towers. However, Bill’s place in the third form is under threat when she is accused of spending too much time in the stables.

Gwen is outraged when she is tricked into signing up for the lacrosse team. However, it is short-lived when she discovers Mary-Lou is out of sorts and needs her help.

Bill is struggling with her school work due to spending too much time at the stables. However, she and Darrell need Thunder’s help when someone at school has a serious accident.

Darrell’s temper rears its head again when Miss Johnson introduces tough new school rules – but can she hold it together during a lacrosse match in front of the county scout?

Sally returns to a very different Malory Towers. The girls need to warn Miss Grayling of the strict new rules, but they will have to get through Miss Johnson first.

Gwen’s power goes to her head when she organises a dance lesson with the boys from Thackerton. Meanwhile, Darrell and Mary-Lou make a mysterious discovery in the woods.

Darrell is determined to give her sister Felicity a jolly fun time when she visits. However, with Miss Johnson’s rules in force, they have to resort to drastic measures.

The girls wreak havoc in Mam’zelle’s class after receiving a surprise package from Alicia. Meanwhile, Darrell prepares for the lacrosse trial.

With the third form on a trip to the circus, Darrell and Sally attempt to recover the confiscated peaches from Miss Johnson’s office. However, they find more than they expected.

Bill’s desire to see Thunder intensifies after he becomes unwell. When Matron suspects it may be something more serious, Darrell and Bill race to get help.

Ron shows Darrell and Sally a stash of art found in the stables - but where did it come from? Miss Johnson is caught off-guard when Miss Grayling arrives back at Malory Towers.

With Darrell focused on clearing Ron’s name, Mary-Lou and Ellen uncover new information that changes everything they thought about the art thefts.