A young girl living in a modest suburban home receives a tiny enchanted key from her godmother and uses it to enter a sequence of whimsical, episodic adventures. Domestic details and beloved pets, including a green-headed canary and a white cat, frame encounters with fairy folk and strange beings—Sweet William, a merman, Queen Mab, twin sisters, and the White Létiche—who tell their own stories. The narrative alternates storytelling and small moral incidents, showing how the key opens doors to unexpected good fortune, friendships with spirits, and a gentle transformation in the girl's everyday life.