Summer Days hentai is based on a visual novel game that serves as a spin-off to the popular 2005 game School Days. However, unlike its predecessor, Summer Days takes place during summer vacation, a few weeks before the start of the second semester in a Japanese high school. It is important to note that while the events in Summer Days happen before the second semester starts, they are not a prequel to School Days. The game revolves around the story of Setsuna Kiyoura and her experiences during summer vacation.
As Setsuna enjoys her break from school, Sekai, her close friend, falls ill with the mumps. Sekai asks Setsuna to cover her part-time waitress job, and although she isn’t fond of the work, Setsuna agrees to help out. After working for a day, Setsuna tells Sekai that she will cover her shift again the following day, thinking that Sekai’s illness is temporary. Unfortunately, it turns out that Sekai’s mumps are severe, and she won’t be able to work for a while.
Disappointed at having to cover for Sekai again, Setsuna takes a walk to clear her head. During her stroll, she runs into Makoto, who is playing with his younger sister Itaru. Although Setsuna and Makoto are acquaintances, they haven’t had many interactions. As they start talking, Setsuna realizes that Makoto is a kind and caring person, and she begins to develop feelings for him.
Summer Days follows the same format as the previous Radish series of games, with a focus on the Radish Restaurant and its original characters. The game explores the characters’ relationships and reveals details about their lives before the second semester starts. For example, the game sheds light on the parentage of Sekai and Setsuna and reintroduces characters from the previous game, such as Youko Inou, Mai Inou, and Shun Hazama, who are now adults.