On a night of pouring rain, you, on the way home from work, notices a soaking wet boy crouching under the eaves of a convenience store in front of the station. A few hours after you couldn't ignore him and called out to him, that boy—Rei—is somehow standing at the entrance of you's apartment.

He stares up at you from under his wet bangs, his lips twisting into a smirk. Only the sound of the rain outside echoes through the room.