Darrell Rivers, Sally Hope and Gwendoline Mary Lacey arrive at Malory Towers at the beginning of a new term. Darrell is hopeful to leave her past behind her, feeling she has a fresh start at this new school.
Gwen is determined to find out the truth about Darrell's old school and sneaks off campus to the village to find a telephone box to ring her cousin who attends St. Hilda's. Darrell runs after her trying to save the form from Matron.
Darrell starts helping Alicia to play pranks in class, whilst a mysterious red hand print appears on the door of the dormitory-could it be from the ghost of Lady Jane Malory?
Sally falls ill, her tummy problems beginning. Darrell is brought into fill in for the big lacrosse match against her old school, St.Hilda's where she faces off with her old teacher, who is secretly abusing old classmate, Penelope.
The girls have their first midnight feast but when Matron nearly catches them, they seek refuge in Miss Grayling's office finding the exam paper answers. Gwen sneaks behind the others backs to read the paper jeopardizing the exam.
It's open day for Malory Towers, Darrell is still confused about Sally. Gwen drags Mary-Lou into afternoon tea with her mother. Gwen's family relationships come to light.
Sally has fallen seriously ill and is need of dire help. Thinking it's her fault, Darrell runs away into the night to find her farther who is a doctor.
Sally's mother has come to Malory Towers wanting to pull her daughter out of the school after receiving Darrell's letter. Not wanting to leave Sally goes off to hide, her family situation ships coming out.
A beautiful dress has made its way to Malory Towers. When Gwen realises there is a debutante she drops Pamela's monitor job, Darrell taking her place. Darrell meddles with Pamela's after school life when she finds out she's the debutante.
Sally and Darrell hatch a plan to make Mary-Lou braver than she could ever imagine, making Darrell "drown" distracting the life guard and leaving Mary-Lou to be the only one who can save her. Gwen gets upset about Mary-Lou making friends.
Darrell and Sally solve the ghost mystery, leaving to the truth about the Lake Family and Emily's mother's condition, causing Matron to take away her job.
Someone stomped on Mary Lou's expensive pen. All the clues point to Darrell, but Sally doesn't believe it. Sally sets out to find the real bully before the bus comes to take them to the train.
