Bored step-siblings, Michelle and her brother, find themselves alone in their shared home. Unbeknownst to each other, they begin to masturbate, Michelle in the bathroom, her brother in his room. Caught in the act, they argue, but the tension between them shifts. Naked and aroused, they decide to explore their mutual attraction, Michelle admiring her brother's thick cock as he strokes it. As they're about to cross the final line, someone's arrival forces them to halt their incestuous encounter.