A fight between Hikari and her husband Yusuke leaves a ten-centimeter hole in the thin wall separating their apartment from Hideki's. With no quick way to repair it, Hideki and Hikari gradually begin communicating through the opening. Unable to ignore the lonely married woman after seeing how coldly her husband treats her, Hideki becomes increasingly drawn to Hikari, leading them into a secret five-day affair and deep doggy-style pounding through the wall.