After a night of partying with his friends, Chan-woo wakes up in his noisy neighbor's room next to a bloody dead body.

What happened last night? When I wake up with a terrible hangover, I find myself in an unfamiliar room. It's room 404 next door, which has mesmerized me with the noise between the walls. So is the dead person here, the owner of the house? And is the culprit... me?—bilalkamaran