The main character returns to his hometown to visit his parents and meets his cousin Umi again. He quickly realized that his cousin was now an extremely hot teenager (18+), and he even had the opportunity to peek at her naked body while taking a shower. This turns him on so much that he starts lying in bed thinking about her. Umi finds out about it and after realizing that her cousin is still a virgin, she takes complete control of the situation and playfully orders him to continue masturbating. The cherry blossom explosion occurred the next morning. And a perfect cousin relationship followed. Yatsugake Umi has an incredibly perfect body. She's too good.
