A summer night, in a red house with blue shutters bordered by the forest. We hear the river flowing from the room where Sister, four years old, wakes Brother, ten years old. Because she has decided: tonight they will go swimming. Through the open window, the two children slip into the darkness. They slip between flowers, brambles, trees... And finally it is the water, the reflection of the stars, their two bodies at rest. But in the distance the storm is rumbling. It is already necessary to return. Brother and Sister go hand in hand. Suddenly, Brother disappears. Sister chases him, runs out of breath, spins around, despairs. Is it a game of hide-and-seek? A trick of the forest? Or is it her memory which, years later, plays a cruel trick on her ?