Cardfight!! Vanguard features a world where the game Cardfight!! Vanguard is becoming the latest craze among trading card games, becoming a part of everyday life for people all over the world. The game is not limited to Earth alone; battles between the creatures used by the players take place on another planet called Cray. The story begins with Aichi Sendou, a timid middle schooler whose meek attitude often leaves him a target for bullies. Aichi was given a very rare card, "Blaster Blade", when he was very young. It's his one treasure that gives him hope. That is, until it gets taken from him. Although Aichi has never played Cardfight!! Vanguard before, he challenges the thief to a game in order to win the "Blaster Blade" back. This high-stakes game quickly draws Aichi into the world of Vanguard battles, which will test and change his worth as both a player and a person.

After pulling the plug on the space reality TV show "Can I Destroy the Earth? 2," the Defense Club and the Conquest Club return to their peaceful high school lives. Time has passed since that fearsome battle, and it's now autumn. The five Defense Club members have stopped serving as the Battle Lovers, and are enjoying a soak in the Kurotama Bath like always, when the Conquest Club broaches a subject that will change a great deal about events to come... [Source: Crunchyroll]

About to enter junior high school, Karada Iokawa is a cheerful and reliable girl, who hates being treated as a child more than anything. After her parents' deaths, her older brother, Hiro, comes back from studying abroad to take care of her. His ex-girlfriend Shouko Nogami, a composed yet sometimes childish and stubborn young woman, follows him to Japan in order to find out why he left her. Between the two girls, the atmosphere is tense, which eventually leads to Shouko calling Karada childish. Later, Karada stands before a shrine praying to grow up. Little does she know that the shrine wishing stone would grant her wish. As Karada grows older, at the same time, Shouko, who happens to be nearby, finds herself a child once again. With their ages now reversed, Shouko and Karada must come to terms with one another and ultimately themselves.

The series was originally planned to be 20+ episodes but was cut short due to unknown circumstances. These specials released on the 7th DVD volume continue the story.