Jae-shin has lived a life of endless pleasure as the son of King Yeom-ra of the underworld. Indulging in nightly pleasures with ever-changing bedmates and stirring a bit of chaos in the mortal realm, Jae-shin lives a blissfully hedonistic life. Until his insolence goes a step too far. As punishment, Jae-shin becomes a powerless puppy during the day, but by night, he’s human. To free himself, he must win over a human’s heart. But when the human who catches his eyes is the sweet-natured prince Lee Nok, Jae-shin may find that his heart is affected the most.