A lawyer, Aiko, and a veterinarian, Kai, meet while walking their dogs, which are instantly drawn to each other; a Korean chaebol heir, Seo-ha, arrives in Japan with a purpose.

Seo-ha claims Kai's dog is his; Aiko, as a lawyer, tries to find a legal way for Kai to keep the dog; Seo-ha takes Aiko on a date in Yokohama.

Kai's dog is suddenly kidnapped; he suspects Seo-ha, who denies any involvement; Aiko reveals to Kai that they share a past connection involving a stray dog from their childhood.

Kai reluctantly agrees to live with Seo-ha; at work, Aiko finds herself in a difficult position, forced to legally oppose Kai over the ownership of his dog due to her boss's decision.

An old friend returns with an offer for Kai, bringing back a dark past; tasked to investigate Seo-ha, Aiko instead learns Kai's secrets.

Aiko's confession leaves Kai confused; a new rival emerges as Seo-ha's sister arrives, confesses to Kai and vets Seo-ha for the family succession.