The door never changes, but the rooms behind it do.

Bonsai artist Shiori Ametsuchi never knows where the door will lead her next. All she is sure of is that whoever she finds in these rooms will be dead before she leaves. Since she woke up without any memory of her past, Shiori has been thrust into a life of walking through a mysterious door and visiting people in their last moments. The door takes Shiori and the souls to rooms containing the present, past, and possibility, experiences the souls need to finally move on.

Shiori is resigned to a life without a past, until she learns that like the people she visits, she is dying too. And Shiori knows too well what happens to people who die without knowing who they are. They get lost.

Shiori races to discover her past, accompanied by Aiden, a man who will be dead by morning. While Shiori remembers nothing, Aiden cannot forget a single moment of his life, no matter how hard he tries.

Together, they journey through burning rooms, dark rooms, rooms with monsters and angels, and rooms that aren't rooms at all. As they piece together Shiori's past, they learn the truth that lives between the border of loneliness and living, forgiveness and freedom, and death and dreams.