Due to an accidental slip, Oto finds herself lying on top of Haruto. As the birthday boy, Haruto had asked for a birthday kiss, but he got more lip than he was expecting. But Airi's sudden appearance squashes any chance of a romantic moment. After Haruto leaves with Airi, Oto remembers that she never told him about her encounter with his rival Kei that day...
— Description from Comic Vine community (comicvine.gamespot.com).