A bored, horny sister and brother, both in their late teens, find themselves alone at home. Michelle, the sister, starts masturbating in the bathroom, her fingers plunging into her wet pussy, while her brother, unaware, prepares for a shower. Catching her mid-act, they argue heatedly, but their frustration turns into mutual desire. Naked, they watch each other masturbate, Michelle's eyes locked on her brother's thick, straight cock. Just as they're about to give in to their taboo urges, someone enters, forcing them to abruptly stop.