Cardfight!! Vanguard G follows the story of Chrono Shindo, a middle school student who has chosen a path of chronic boredom and loneliness. However, that all changes when he finds a Gear Chronicle deck in his locker at school. At that point, he has never played Vanguard before and is confused by the presence of Vanguard cards in his locker.
So, he decided to visit Card Capital 2 to investigate. There he meets Kamui Katsuragi, who talks him into playing Vanguard. Chrono finds Vanguard enjoyable, so he decides to return to Card Capital 2, where he takes up a quest and becomes a Grade 1 fighter. Then, he meets and fights Ibuki Kouji, who reveals that Chrono is and always has been completely alone. As a result, Ibuki crushes Chrono with no difficulty and refuses to even tell Chrono his name until Chrono becomes stronger. Over the next few days days, Chrono meets and befriends Shion Kiba and Tokoha Anjou. Chrono also makes an acquaintance of Mamoru Anjou, the Kagero clan leader, and Jaime Alcaraz, the Spanish ace of the European League.