Who is the murderer of a question mark case that happened in an ordinary place in the Republic of Korea? From a security guard full of stories to an excluded teenager who is bent on revenge. A local idol with a poker face. An elementary school student who is suspected of living a second life. This place is full of suspicious neighbors! One day, a sloppy and nosy 'Tae-sung' appeared in front of them, and the peaceful daily life was broken...