Fifteen-year-old Alex is spending the summer with his beloved 18-year-old sister Freya in a farmhouse in the middle of a forest. It is a world of play and dreams, and they live with their younger sisters, their mother and their eccentric father, an aged Russian emigrant. When Alex and Freya are caught by surprise in a very intimate game, however, the familial balance is shattered. The father casts out his son, who manages to rescue himself on the rooftop. Alex swears to Freya that he will never set foot on the ground again and promises to wait for her forever. Moving from tree to tree, he progresses ever deeper into the forest.