Hikaru and his sister have always supported each other. When his sister found the man of her dreams, he decided to leave home, but in the end he was persuaded to stay and now lives happily with his sister and her husband. One day, after working late, he was lulled to sleep by the sound of the train. He heard heavy breathing and woke up to find his brother-in-law stroking his penis while secretly peering up his upturned skirt ......