In an airtight secret room in the suburbs, the light is so weak that it can hardly form a straight line. A man and a woman are unconscious on the ground, and the man has a knife in his abdomen...; The woman wakes up first and finds that the door is locked. She finds a key on the ground outside the door through the crack of the door, but she fails to pull the key back. The man finally wakes up, and he feels pain and fear. During their conversation, they find that each other has lost their memory! This makes the suspicion between the two people increase. The air in the secret room is getting less and less, and the woman gradually loses her mind. She decides to pull out the knife from the man and take back the key, and she succeeds! The two walk slowly out of the room in opposite directions. Later, the man found out that he was the target of kidnapping! He also found a young female corpse on the ground. He remembered that she was his girlfriend. The man got back most of his memories. He pointed out that the woman was the kidnapper. Is she really the kidnapper?