In the confines of their shared home, a brother and sister, drawn together by boredom and proximity, begin to explore their most private desires. She, a curious teen, discovers the pleasure of her own touch, while he, a few years older, struggles with his growing attraction to her. Their private moments of masturbation soon intertwine, as they catch each other in the act, leading to heated arguments and tense silences, until one day, the tension boils over, and they find themselves crossing the line they've long been tiptoeing around.