``I'll come back for your first kiss on my birthday in 10 years,'' Ore Yuuji, also known as Yu, promised his childhood friend Rei that he would come back to America for his first kiss. However, when Yu returns to Japan for the first time in 10 years, he learns that Rei's lips have been stolen by another man. His opponent is world boxing champion Charlie. Putting his man's pride on the line, Yu stands on the stage in what seems to be a reckless battle...