The siblings, cloistered in their secret haven, surrender to their taboo passion. Michelle's hands tremble as she unzips her brother's pants, revealing his throbbing erection. She hesitates, her eyes darting to the closed door, but her curiosity and desire win out. She tentatively strokes his length, her touch feather-light yet electric. Her brother's hands find her breasts, cupping them through her shirt, his thumbs brushing against her hardening nipples. They're teetering on the edge of no return, their bodies quivering with anticipation and fear.