Ko Ichinomiya believes in his family's motto of never owing anyone, but a mishap in the Arakawa River leads to an unexpected debt to the quirky Nino, his eccentric rescuer living under the bridge. Determined to repay her, he commits to helping Nino fulfill her wish to "experience love." His journey introduces him to a colorful cast of characters, including a fiery kappa, a drag queen nun, and an actual rock star, all adding to the absurd charm of his new life beneath the bridge.