The O'Sullivan twins return for their second term at St Clare's determined to work hard and do well. Most of their old friends are back again and there are new girls to size up. Among these are the twins' feathered headed cousin, Alison, the talented and friendly Lucy Oriel, and the surly and bad tempered Margery Fenworthy.

The twins are now firm friends with most of their form and form friendships with some of the second form also. As a result of this they are invited to a midnight feast with some members of the second form to celebrate the birthday of Tessie, a second form girl. Erica, an unpopular second former, resolves to disrupt the party after hearing herself discussed in unflattering terms when the others assume that she is not within earshot. The girls vote to ignore Erica after learning that she is the one who gave them away to Mam'zelle, causing Erica to vow revenge on Pat. She begins a campaign of spiteful tricks against Pat.

A classic children’s story from the world’s best-loved children’s author, Enid Blyton. School life has never been so splendid. Pat and Isabel O'Sullivan plan to give everyone at their new school a few surprises. But it's them who are in for a shock . . . Watch out! There's trouble at St Clare's! Enid Blyton is arguably the most famous children’s author of all time, thanks to series such as The Wishing-Chair, The Faraway Tree­, The Mysteries, The Famous Five and The Secret Seven. Her school stories – including the St Clare’s and Malory Towers series are the perfect books for girls who are experiencing their own adventure at school.

The twins arrive at St. Clare's ready to work and play in the summer term as they enjoyed at Redroofs. Will Bobby change and will Carlotta's secret comes out?

The Second Form at St. Clare's is the fourth novel in the St. Clare's series of children's school stories by Enid Blyton. The series is about the boarding school adventures of twin girls Patricia and Isabel O'Sullivan. Their form mistress is now Miss Jenks and they no longer have to bear the severeness of the first form mistress, Miss Roberts – who is extremely sarcastic and firm but can be kind when she feels like it, a bit like Mam'zelle, the French teacher that used to teach and is still teaching the girls.

But Mam'zellle is in for a shock! Out to break every school rule, new girl Claudine is no teacher's pet.

The O'Sullivan twins are now head girls! And two heads are better than one, with the new girls they have to sort out...There's two cheeky first formers - more twins! - and a sulky new girl in the sixth form, Morag. Morag detests St Clare's. She's only happy when she can escape to the local riding stables. The twins are sad it's their last year at St Clare's. Before they leave, will they find out what's wrong with Morag?