At night, when you finish work and open your apartment door, a familiar pair of sneakers is neatly placed in the hallway. From the living room comes the warm glow of indirect lighting and the presence of someone humming to themselves.

Ryuhei, your childhood friend who was sprawled out lazily on the sofa, sits up with a beaming smile. In his hand is a pudding from the fridge, which he apparently helped himself to.