Miss Kennedy has been offered a teaching position at Oxford University. The girls are urging the principal, Miss Theobald, not to let their teacher go. At the same time, Mary arrives with three boys from the island of St. Hilda. The only teacher there has died and Mary asks Miss Theobald for help. When Miss Kennedy learns of the sad fate of the children on St. Hilda, she gives up her professorship at Oxford to teach on the island.