Located in an endless twilight, the Tasogare Hotel accepts anyone trapped between life and death. Unaware of their fate, guests must recover lost memories through mementos hidden in their assigned hotel rooms. Most guests pass on or return to the world of the living within days, while a few others find themselves staying at the hotel for much longer than usual. Neko Tsukahara, a young woman with an expressionless face, finds herself at this hotel. As she is guided by the staff, Neko regains enough memories to become invested in the plights of the other guests. Solving the guests' affairs and the mystery behind the hotel proves too interesting a situation to ignore; Neko decides that simply being a guest is not enough to satisfy her curiosity.