Two scientists are attempting to distribute the cure for a demon virus that is affecting people all over Japan, however, things have become complicated. One of them has become infected. So begins his battle with himself, as he attempts to not only control his emerging demon side, but also to save the lives of others by wielding its great strength.

Aika's story continues, she is now 19 years-old, 3 years older than in R-16 and 7 younger than in Agent AIKa. Strange phenomena have been occuring at a girls academy. Slowly but persistently the most cute and beautiful girls are joining an internal club, but instead of a sing-in they just get abducted by a strange being that takes control over them by some indecent means. By coincidence Aika was flying-by on her plane when one of this abductions occurred and she was attacked to prevent her from comming closer, but instead of repelling her, she is intrigued about the attack's origin and then the opportunity shows up when her late partners from R-16 decide to investigate those abductions. The story remains full of action and panty flashing that are a must in Aika's series.

A catastrophic earthquake has left Tokyo, and most of the Earth for that matter, under the sea. Aika is a salvager who retrieves various remains from the watery ruins. When Aika accepts the dangerous mission of locating and obtaining the mysterious Lagu, she discovers that she's not the only one after it.

There are eleven girls that consist the C-class Ongaku Shoujo idol unit under Pine Records. Despite generating red sales marks and not being very popular, Producer Ikebashi and the members are trying their very best to up their levels. Nevertheless, Ikebashi suggests recruiting a new member for Ongaku Shoujo; someone who can act as a catalyst for the success of the group. Thus, an audition was opened, leading to the soon-to-be legendary group's meeting to a girl named Hanako. (Source: MAL News)