Kids from all over town converge to play Vanguard, a card game that seems to be the biggest thing going around. A timid boy, Aichi Sendou, has a rare card, the Blaster Blade, which makes him a target for Katsumi Morikawa, a player who wants to use Aichi's card to get revenge on another player, Toshiki Kai. After school, Morikawa and his buddy Y?ta Izaki steal Aichi's Blaster Blade from him. Aichi runs to a card shop called Card Capital to find that Morikawa lost it in a bet against Kai. It is then that Aichi and Kai meet and play a game of Vanguard with Blaster Blade as the prize. Before the match, Kai gives Aichi Blaster Blade for the sake of completing Aichi's deck. During the course of the match, Kai teaches Aichi the rules of playing Vanguard. As the fight goes on, Aichi reveals that he has met Kai before when summoning him ace, Blaster Blade, which Kai gave to him long ago, stating that it was because of him that he wanted to get into Vanguard.