Philathea Marriott returns to the Abbey High School for the Christmas Term to discover that she and two of her friends, Dorcas Boyd and Dorinda Chesney have been moved up, but Agatha Finlayson is left in Upper Fourth. Two new girls, Beatrice Lowe and Brenda Lowe (who are not related) are also members of the Fifth Remove.
It soon becomes clear that Brenda, who is from a wealthy family, looks down on the girls who are not well off, and opposes the school atmosphere which is utterly unsnobbish. She is particularly contemptuous of Philathea, whose father owns a bookshop, and of Beatrice, who won a scholarship to the school.
A feud erupts between Brenda and her friends, including Lotty and Adeline, the most badly behaved girls in the school, and the rest of the form. Several conflicts occur within the form, including Philathea's selection of the netball team. There are also difficulties outside the form, as Brenda and her friends defy the prefects, including Vida, Philathea's sister. Matters come to a head when a quarrel between Brenda and Philathea leads to a terrible accident, but the term ends happily when the feud is finished.