Aika is a smart and athletic high school girl. She is so competent that she successfully passes the salvagers license test, obtaining a C-class license. Yet, she is young and hotheaded, so much so that Gota still treats her as a child. Due to this personality, no one is willing to hire her for salvaging jobs.<br><br> Since she had taken the trouble to get her license, she decides to post an ad in her school to attract clients. She manages to get the attention of Erika, a daughter of a rich family and the leader of the treasure hunting club. She asks Aika to salvage something from the sea and Aika delightfully accepts the request.<br><br> However, upon seeing the state-of-the-art submarine loaded onto Erika's private cruiser and discovering their destination, Aika realizes the terrible nature of her assignment. This results in a clash with a group of high school girls in the southern islands.<br><br> Who is the mysterious girl named Karen? So begins Aika's newest challenge!<br><br> (Source: AnimeNfo)