Her childhood friend, Sou, returns from America for the first time in 5 years. Ai is really happy to see that he has become very angelic looking in the time that they've been apart. However, one day he says, "I will definitely make Ai mine", and forcibly kisses her! To get treated like that by someone three years younger than her and who she's always treated as a younger brother takes Ai by surprise. It would definitely make Ai's heart skip a beat, wouldn't it?!