Kagura Mio is the manager of her high school swim team. Three of the first year boys on her team, though, spend all their time bickering and mocking her idea of "teamwork." Then a fourth boy joins the team, who supports her idea of competing as a medley relay team. Each of the boys is extremely skilled in one of the four strokes—backstroke, breaststroke, butterfly and freestroke—but three of them insist that they are "sharks" and won't swim together. Will she be able to get these skilled swimmers to work together as a team?