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

Miss Johnson enforces a list of tough new rules which get the better Darrell’s temper. An important lacrosse match is at stake when Darrell is given a particularly difficult punishment.

Bill will stop at nothing when she discovers that her horse Thunder is sick with colic. Gwen is charged with keeping Bill away from the stables or else they will both be punished.

Alicia convinces Darrell to help her play a prank on their teachers with invisible chalk. Meanwhile, Mr. Parker becomes stricter with his teaching. Mary-Lou finds her voice and stands up for herself.

The girls attempt to make Ellen feel more included but their efforts backfire. Miss Grayling has a secret that might put Malory Towers in danger.

Miss Grayling reveals disheartening news. In one last attempt to save the school, Darrell and Sally try to find Lady Jane’s lost treasure. Gwen’s secrets come to light.

Sally returns to a very different Malory Towers after her case of the mumps. The strict new rules keep Mavis and Irene from their audition, but the girls have a plan to cover for them and keep Miss Johnson at bay.

A beautiful dress arrives at Malory Towers: one of the girls is a debutante, destined to marry into aristocracy. When Darrell finds out who the mystery girl is, she's determined to prove the girl is a poor choice.

Feeling guilty for lashing out at Mary-Lou, Darrell and Sally hatch a plan to give Mary-Lou the confidence she needs. But will the plan backfire and make Mary-Lou less courageous?

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.

Darrell shows a potential investor around Malory Towers. Gwen is confronted with her lies when her mother visits.

Gwen resorts to drastic measures to hide what she’s stolen. Darrell and Sally find a clue that could finally lead them to Lady Jane Malory’s treasure.

Darrell suggests a midnight feast in the stables, but they’re afraid of horse poachers. Mavis, a sixth former, is on the hunt for someone to accompany her on the piano for an important audition, and Irene might fit the bill.

June and Darrell find themselves in danger when they leave the school to continue the search for the treasure in a cave during high tide. The rest of the school prepares for the wedding. Irene is given an important task by her father.

Darrell is up to play in the lacrosse game, but her excitement is short lived when she finds out they'll be playing against her old school. Darrell must face her past and overcome her temper if she wants to win the match.

May-Lou is devastated to find her courage pen smashed on the floor. When Darrell's shoes are found with ink on them, Darrell is the prime suspect, and the North Tower holds a class court.

Darrell and her class return to Malory Towers. The first order of business: elect a new class leader. Gwen decides to take the new girl under her wing and become her best friend.

Malory Towers competes with the local boys' school in a competition. Ellen suffers a panic attack when she is accused of Gwen's misdeeds.

Alicia sends a package for the girls filled with goodies and prank materials, plus a secret message. Darrell prepares for the lacrosse trial and sneaks in practice time.

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

After a confrontation with Darrell about her family, Sally is found hiding in pain. However, her injuries are far more serious than first thought. Fearing she is at fault, Darrell leaves the school to find a doctor.

Darrell is itching to get to the bottom of Sally's relationship with her family, but when Sally goes missing, the first form rallies together to comb the grounds. Darrell and Sally finally discover the real reason Sally was sent to Malory Towers.

In the dead of night Mary-Lou faints when she sees a hooded figure in the dorm bathroom. Not wanting Mary-Lou's courage to be crushed, Darrell and Sally are determined to get to the bottom of the mystery.

Alicia and Darrell pull a sneezing prank on their French teacher, which disappoints Sally. Someone has stolen important possessions from the girls.

Bill struggles to balance her schoolwork with time spent at the stables with her horse, Thunder. Bill and Darrell need Thunder's help when someone at the school has a serious accident.