Airi convinces Oto to participate in Eitoku and Momonozono Academies' joint summer school on an island resort. With Airi's support, Oto is determined to enjoy this last summer of high school in spite of Haruto's animosity toward her. But fate has other plans when Oto and Haruto wind up on the same snorkeling trip!
— Description from Comic Vine community (comicvine.gamespot.com).
