Mary, a curious and horny teen, retreats to her room to indulge in some private time, her fingers dancing over her clit, bringing herself to the brink of ecstasy. Unbeknownst to her, her brother has been watching through the cracked door, his cock hardening at the sight of his sister's forbidden pleasure. When she catches him watching, she's outraged, but the tension between them is undeniable. Later, they find themselves alone together again, the air thick with unspoken desire.