In a cramped Taipei apartment, two siblings, isolated and restless, turn to self-pleasure for comfort. The brother, hidden in the bathroom, strokes his thick cock as his sister masturbates in the bedroom, her cries of pleasure echoing through the thin walls. Caught off guard, they argue, but later, curiosity and desire overcome them. Naked, they explore each other's bodies, the sister's pussy dripping with anticipation as she imagines her brother's cock inside her. Just as they're about to cross the line, a knock at the door forces them back into the shadows of their secret.