A young brother and sister, bound by blood but drawn to each other's bodies, find themselves in a taboo dance of desire. Their home, a pressure cooker of unspoken lust, explodes when they're left alone together. She fingers herself, he strokes his cock, and their mutual masturbation session turns into a heated argument. But soon, they're back to their forbidden game, naked and panting, ready to cross the ultimate line until an unexpected intrusion forces them apart.