The adventure never ends when Lucky O'Leprechaun is around. Returning for a third adventure, Jana Dillon's lively trickster inadvertently helps a little boy adjust to a new school.
When Mr. Eliot's class discovers someone has taken bites out of Lydia's birthday cupcakes, everyone suspects the new kid, whose name no one can remember. Then, something takes tiny bites out of their cookies at snack time. Thinking it must be a mouse, Mr. Eliot sets a trap no mere rodent could spring. When they return the next day, the cheese is gone, and there's nothing but a pencil stuck in the trap.
Knowing that his cousins once caught a leprechaun in the same neighborhood, Kevin O'Malley lets the class know that he thinks Lucky O'Leprechaun is the culprit and tells them how they can get him to grant a wish for a trip to the moon. It's a wild ride when Lucky O'Leprechaun is around, as he continues his pranks on unsuspecting humans and occasionally even does a good deed.