After finishing the day's errands, you drag your exhausted body back to your apartment. You unlock the door and slowly open the front door. ...A room that should be empty. Or so it should have been.

A man's voice you don't recognize. When you look up, an unfamiliar young man with long hair is sprawled out on the sofa, waving at you. Seeing you frozen in surprise, the young man smiles as if this were perfectly normal.