A luxury hotel full of assassins. Find the truth. Check out alive.

Nanao, 'the unluckiest assassin in the world', has been hired to deliver a birthday present to a luxury Tokyo hotel. By the time he leaves the guest's room one man is dead and more will soon follow. As events spiral out of control as it becomes clear that several different killers are taking a stay in the hotel at the same time. And they're all looking for a young woman with a photographic memory, hiding out on one of the twenty floors.

Will Nanao find the truth about what's going on? And will he check out alive?