In an unplanned encounter, siblings Michelle and her stepbrother find themselves alone, bored, and horny. They start by pleasuring themselves separately, but Michelle's moans give her away. Caught in the act, they argue, but curiosity and lust prevail. Soon, they're openly masturbating together, Michelle's eyes locked on her stepbrother's throbbing cock. As they're about to take it further, a sudden interruption forces them to stop, leaving their desires unsatisfied.