A father and son having sex in front of the father's grave, a father and son having sex in the mountains while on a trip, a father and son having sex in an open-air bath. A son who is lustful for his mother's body seeks her body regardless of the surroundings, and his mother, feeling sorry for him, responds to his request even though it means having sex in the open. Under the blue sky, the sex between the mother and son, who have become open-minded, continues endlessly.