Yotsuya and Ichinose are enjoying a hot afternoon when they recall the time that the tenants of Ikkoku-kan and Mitaka go off on a cruise to party hard aboard Mitaka's new boat; however, the boat falls apart, and everyone is shipwrecked on a deserted island. With everyone up to their usual antics and shenanigans, what can happen in such a desolate place?

When Keita Suminoe's father remarried, not only did he gain a new mother, but elder twin sisters as well. Distinct yet similar, the homely and mature Ako is a former student council president, while the athletic and aloof Riko is the previous disciplinary president. The three of them have been together since kindergarten, resulting in a deep bond between the siblings. However, over time, their relationship developed into something more romantic—and erotic . Now in his last year of middle school, Keita has already received a sports recommendation, but it's from a different high school than his two sisters. Disappointed, both sisters try to change his mind, and he agrees, giving in to their desperate pleas. Unaware of the consequences, he now has to attempt to study for his high school exams while warding off the advances of his lust-driven sisters. With their parent's blessings, Ako and Riko strive to be Keita's future wife, leaving him to try his best to keep the relationship between them strictly platonic. However, with two beautiful girls vying for his attention, will Keita be able to withstand the endless temptations? [Written by MAL Rewrite]

An extended version of the second season's first episode, which is under the same title.

In 2029, Scrooge escapes from a research facility where he had been confined as an experimental subject. His body was remodeled by genetic manipulations and he uses his psychic power to kill the chasers. One day, he meets another experimental subject called Carol. When three psychic chasers hunt down the two, Carol asks Scrooge to use his right arm to extract a weapon from her body.