Rachel Gardner, a 13-year-old girl who wakes up at the bottom of a building, has no memory and doesn't know why she is here. In order to return to the ground, she starts trying to escape, but suddenly a killer with a bandage on his face and a sickle like the god of death appears in front of her. "Please, kill me." "Help me get out of here. If you do, I will kill you." The strange bond between the two gradually deepens with the "absurd promise". What exactly is this place? Why are the two imprisoned here? What fate awaits them? The journey of escaping from the closed building with a sense of death has begun. Will the two be able to stick to their promise and escape the building safely?