In this French-language taboo tale, siblings sheltering from a storm find themselves in a cramped attic, their bodies pressed together as lightning illuminates their tense faces. The brother, a scientist, lectures about the cosmos, but his sister, a devout Catholic, can't focus, haunted by her desires. As the night grows colder, their breaths misting in the air, she can't ignore the growing bulge in his pants. He, too, struggles, his scientific detachment melting under her proximity. Their bodies inch closer, their eyes locked, as they debate the laws of the universe and the taboo they're about to break.