Humphrey usually helps solve problems, but now he's caused a big one: Golden-Miranda gets in trouble when Humphrey is caught outside of his cage on her watch. No one knows about his lock-that-doesn't-lock and he can't exactly squeak up on her behalf. While Humphrey manages to show Pay-Attention-Art that math is important outside of class, help Sit-Still-Seth actually sit still, and survive a trip to the vet, can he clear Miranda's name without giving up his freedom forever?