What happened in 520?
A letter arrives with no return address — just a key and a number. 520.
The apartment belonged to someone you used to know. Now it's yours, supposedly. But the locks have been changed, the neighbors go quiet when you ask, and the place is exactly as it was the day everything went wrong — coffee still in the cup, a record still on the turntable.
Over one long night, you'll move room to room, picking up the small things people leave behind: a half-written letter, a photograph turned face-down, a calendar with one date circled hard enough to tear the paper. Each clue you examine reshapes what you think you know. And every so often, the story stops and waits — because what happens next is up to you.
Apartment 520 is a narrative mystery in the spirit of a great short story: no fail states, no busywork, just you, a quiet room, and the slow pull of wanting to know the truth.