Tired of the fast-paced city life, Izuki has agreed to take care of his uncle's house in the mountains, which are said to be "visited by yokai."
Izuki, dismissive of the superstition, goes exploring - only to be attacked by a yokai in the woods. He's saved by a beautiful man named Haku, who claims to be the incarnation of a komainu guardian dog. He pledges himself to Izuki and begs him to be his master. Izuki refuses at first, wanting to return to the city as quickly as possible, but is swayed by Haku's lonely eyes and brings him back to the house. Gradually, he falls into a comfortable rhythm with the pushy but devoted Haku while living under the same roof, and Izuki wonders if he really wants to return to the city as he thought.
However, Haku harbors a secret that could put Izuki's life at risk. Will Izuki and Haku come together in the end, or will Haku succumb to the loneliness that he's held at bay for centuries...?