Aika is an intelligent and athletic high school student. She is so capable that she passed the salvagers license test and received a C-class license. She is, nevertheless, young and impulsive, to the point where Gota still regards her as a child. No one wants to recruit her for work salvaging because of her personality. She chooses to place an ad at her school to attract clients because she went to the hassle of getting her license. Erika, the treasure hunting club's head and the daughter of a wealthy family, is attracted to her. She requests that Aika salvage something from the water, which Aika gladly accepts. However, when Erika saw the state-of-the-art submarine carried aboard her own yacht, she was blown away.