Deciding to spend his summer vacation at his grandmother's house, Hiroki comes to Ogasawara for the first time in years. He used to come every year as a child, but since entering junior high, he's been unable to make the trip due to his parents' works and some other circumtances. So this year, he came to the island on his own. Having come to the island partially for a bit of self-discovery, he encounters a girl who needs even more self-discovery than himself. Hiroki has bright personality and is big-hearted, but also has some strong feelings and ideas when it comes to food. He even plans to acquire his cook's lisence and become a chef after graduating high school. Thanks to his participation in various school sports clubs, he's very athletic and is an excellent swimmer. In the past, He was once a scuba diving buddy of Chisa. "I'm a sucker for adventure. It runs in the family."