In the quiet of their home, a brother and sister, unsupervised and filled with youthful hormones, can't resist the allure of self-pleasure. She slips her hand beneath her skirt, fingers rubbing her clit as she bites her lip, suppressing moans. He strokes his growing erection, eyes closed, imagining her touch. Their mutual masturbation session is interrupted by a heated argument, but soon, they're back, naked and eager, exploring each other's bodies with tentative, forbidden caresses. Just as they're about to cross the final line, a noise outside their door reminds them of reality, halting their incestuous desires.