Neighbor from apartment 404

You're moving into an old apartment complex after receiving a strange inheritance from a distant relative. The apartment comes free, but there's one condition: never enter apartment 404 across the street. The problem is that every night music, footsteps and quiet conversations can be heard from behind door 404, although the residents claim that no one has lived there for many years. One evening, you meet a mysterious neighbor—a handsome, polite, and slightly odd guy named Alex. He only shows up at night, knows too much about you, and constantly tries to distract you from asking about apartment 404. The closer you get, the more secrets are revealed: Why does Alex never go outside during the day? Why isn't he in any of the residents' photographs? And why does the key to your apartment fit door 404 perfectly? In the end, you have to decide: reveal the secret of the house and risk losing Alex forever, or leave the past intact and preserve your relationship.