Pero, a sword-wielding cat-in-boots sentenced to death for sparing a mouse, escapes his execution and embarks on a journey. Along the way, he teams up with a company of bandit mice and Pierre, a gentle orphan who has been cheated out of his inheritance.

When Pero learns that Princess Rose is seeking a husband, he becomes determined to make sure that Pierre is the one chosen. However, Princess Rose is forcibly betrothed to the wicked ogre Lucifer! Pero begins to spin a web of lies to enthrall Rose with Pierre, but Pero's boasts are far from the truth. Pierre has to keep up with Pero's bold image of him but is frightened, because while Princess Rose is charming, loving her means going against the Devil's wishes.