This story takes place a little further in the future—There are now billions of card game players in the world, to an extent where card games have become a necessity, a part of our lives.The protagonist of this story, Aichi Sendo, is a timid boy in his third year of middle school. He had been living his life looking backward rather than forward, trying not to stand out. However, he had one thing that kept him going - the Blaster Blade, a card from a card game that was given to him when he was little. That card is the reason why he begins to engage in Cardfights, something that changes his life drastically.The name of the card game is Vanguard. The game takes place in a different planet called Cray. It is a place similar to our own planet, but unlike planet Earth, Gods and Demons, Dragons and other mythical creatures still roam the land. It is also a world where both Magic and Science have advanced hand in hand. Countries with advances in different fields and cultures rule over different parts of the planet Cray. And due to a never before seen play system, it becomes popular throughout the world.Aichi, immediately attracted by Vanguard, meets friends such as Misaki Togura and Kamui Katsuragi, along with other rivals. Through friendly rivalry with them, Aichi begins to enjoy a fulfilling life. Aichi, however, has a goal: to once again battle with a Vanguard Fighter by the name of Toshiki Kai. Toshiki Kai is an aloof and cold-hearted high schooler who has outstanding abilities in the world of Vanguard. He is also the reason why Aichi started playing the game. For him, Kai is the person who saved him from his boring life and introduced him to Vanguard. In order to get better at Vanguard, Aichi puts his soul into it every day. He wishes that someday, he'll be able to battle Kai and have him recognize his worth.