Elizabeth is appointed a monitor for the term, a position that makes her feel both proud and responsible, but also somewhat bored and lonely. Meanwhile, four new children join the school, including Julian, a clever but lazy boy, and Rosemary, a timid girl. When money goes missing from Rosemary's purse, Elizabeth becomes suspicious and attempts to catch the thief. However, her actions lead to a series of misunderstandings, and she finds herself facing challenges as she tries to uncover the truth.