In the dim light of their shared bedroom, a brother and sister, drenched from a sudden storm, find themselves entwined in a web of desire. The girl, her soaked nightgown clinging to her curves, notices her brother's bulging erection. She tentatively reaches out, wrapping her fingers around his hardness. He gasps, his hips bucking slightly. They lock eyes, the weight of their taboo act hanging heavy in the air. She strokes him slowly, feeling his length pulse in her hand. He reaches for her, slipping his fingers into her panties, finding her wet and ready. They explore each other's bodies, their breaths coming in ragged gasps, until they're interrupted by a knock at the door.