The creaking floorboards and the distant hum of the television are the only sounds that punctuate the siblings' secret ritual. The brother, his heart pounding in his chest, watches as his sister slowly unbuttons her blouse, revealing the lacy cups of her bra. She shivers as he traces the edge of the fabric with his fingertips, his touch sending electric jolts through her body. She can feel his erection straining against his jeans, and she reaches out, tentatively at first, to stroke him through the denim. Their eyes meet, and in that moment, they both know that there's no turning back.