A Japanese mystery bestseller, revolving around a series of unsettling floorplans, in which the reader is the detective - from the Youtube sensation Uketsu.

A mysterious windowless room on a house's floorplan hints at a hideous secret. A young girl suspects that her cousin's seemingly accidental death was the result of a sinister family tradition.

Can you uncover the dark secret of these strange houses? When you do, an unforgettable truth will be revealed.