Synopsis

Born and raised in a family that everyone envies, brothers Cho Kyu-bin (Bottom) and Cho Eun-bin (Top) are so bad that they haven't had a proper conversation with each other for over 10 years. Then one day, Eun-bin suffers from memory loss and regresses to the age of elementary school due to an unexpected accident. Kyu-bin takes responsibility for the accident and decides to take care of Eun-bin. When Eun-bin was having a hard time dealing with her younger sibling who was acting like an adult, crying and clinging to her, Eun-bin secretly visits Kyu-bin's room late at night. "Hyung, my dick hurts." Kyu-bin looks at his younger sibling who is sobbing without knowing what an erection is or how to relieve that desire through masturbation, and ends up having sex with her half-heartedly. Gyu-bin realizes his mistake, but thinks, “I’ll just play around with it until my memories come back. Anyway, once my memories come back, that kid will be embarrassed and won’t be able to tell anyone.” and ends up falling into a swamp from which he can no longer get out…