A brother and sister, bored and alone, turn to self-pleasure to pass the time. The sister, Michelle, fingers her wet pussy and strokes her big ass, trying to be quiet. Her stepbrother catches her in the act and they argue, but later make amends. They decide to masturbate openly in front of each other, Michelle taking in her stepbrother's thick, straight cock as he jerks off. Their mutual desire grows, and just as they're about to act on it, someone enters, forcing them to abruptly end their intense, forbidden encounter.