A mysterious invitation leads to the attic of an abandoned house. In the room is a cast-iron safe laced with strange carvings and on top, a note from your distant companion. It promises something ancient and astonishing concealed in the iron chamber - you need only find a way in.

The game has a minimal story, in which the player is told by letters of a mysterious box in a room in a house; as the player solves the puzzles around the box, more notes from the same author - one who previously had solved the mystery of the box - are found, describing the box's use of an ethereal material called "Null", as well as showing the author slowly descending into madness.