The existence of these alternate personalities, and the relationship between them, has some mysterious connection with Sora's fall from the window and his forgotten past.

Because Yoru and Ran possess them arbitrarily, Sora and Sunao frequently find themselves in embarrassing situations when they regain control of their minds.

Other comical situations arise from Matsuri's efforts to draw Sora and Sunao into his moneymaking schemes, known as the group "The School Do-It-Alls" and from such minor characters as a bishōnen ghost and three younger boys who resemble the trio.

No parents are ever mentioned, and the only authority figures are school nurse Kai Nanami and math teacher Shin'ichirou Minato, but it is known that Sora and Sunao are both orphans.

Both have some connection with Sora and Sunao's dark past, which also involves one of the older students at the school, Kai Nagase, and a mysterious doctor named Aizawa.

The games were originally point-and-click visual novels released for Windows, containing sexual content, though certain body parts are censored (as is all pornographic material in Japan).

After being released from the hospital, Sora heads back to the dorms to find that a new boy by the name of Sunao Fujimori, who will now be his roommate.

As he spends time with Sunao, he notices some strange things about him, including his transformation into his alternate personality Ran.

After spending some time in Shin-ichirou and Nanami's place, Sora and Sunao come across a mysterious cosplaying bandit known only by the number 416.

Even Sora begins to notice that something odd about his connection to Sunao and the relationship between their alternate personalities Yoru and Ran.

Collecting all the CGs allows the player to access secret endings that involve Sora, Sunao, Matsuri, Shin-ichirou, and Nanami banding together as cosplaying bandits 848, 370, 332, 416, and 773.

However, he realizes that it won't stay normal for long when he sees that Sunao, who he has not seen since the events in Rain, reappears in one of the halls.

Depending on the player's choices, Sora can either end up with Sunao, Nanami, Hiromu, Matsuri, Soushi, or Minato.

Of the original cast, only Gaku, Nagase, Shiina, Kitamura, Nanami, Nakahara, and Hano make appearances.