Perfect Wall

High school student SeeWoo was playing with his younger sister, SeoYeon, at home when a water balloon that SeoYeon accidentally threw fell through the window, killing the boy who lived upstairs. The only ones who know the truth are SeeWoo and his mother. SeeWoo hesitates out of fear, but his mother strongly opposes his desire to confess.

Jung Soo-yeon, a first-year elementary school teacher, experiences an absurd situation after school when she gets trapped on the school rooftop by her 5th-grade students' pranks. The children lock the rooftop door, mock Soo-yeon, and leave, and Soo-yeon tries to call for help in the empty school but no one is there.