Nestled in their family's sprawling estate, a brother and sister find themselves isolated during a storm, the power outage plunging them into darkness and each other's arms. As the thunder roars outside, the sister, usually so prim and proper, sheds her inhibitions, revealing a hidden wildness that entices her brother. He, a man of quiet strength and unspoken longing, cannot resist her allure. In the cloak of darkness, they come together, their bodies entwined, their moans muffled by the storm's fury. Their lovemaking is feverish, their bodies slick with sweat and the rain that seeps in through a broken window. As they climax together, the lightning illuminates their faces, contorted in ecstasy, and they know that they have crossed a line from which there is no return.