Set three years after the Legion Mate arc, the story now follows the new main characters Chrono Shindou, Shion Kiba, and Tokoha Anjou at Card Capital 2. Familiar faces returns as Shin Nitta is the manager of Card Capital 2 and Kamui Katsuragi as a part-time worker there. Misaki Tokura also appears as the owner of the Card Capital franchise.
Cardfight!! Vanguard G follows the story of Chrono Shindou, 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 Kouji Ibuki, 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, 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.
FIVA is holding a national tournament, and the only one not fired up is Tokoha. Being the younger sister of Mamoru, she is tired of being forced to live up to her brother’s legacy. Meanwhile, Chrono is trying to get to Grade 3 so he can enter the tournament. In the end, Chrono, Shion, and Tokoha form Team TRY3 and enter the National Tournament together.
At the regional qualifier, Team TRY3 fights Team Demise. They ultimately turn out to be a formidable foe. Chrono beats their first fighter with no problems. However, Shion and Tokoha ultimately lose in the second two games. In the aftermath of their defeat Chrono’s aunt discovers Chrono’s new hobby and reveals the truth behind his father, who disappeared 10 years ago because of Vanguard. Team TRY3 visits the United Sanctuary branch, seeking a rematch with Team Demise. They find that the United Sanctuary branch is turning fighters into people obsessed with winning and are challenged by the Branch Manager himself. Unbeknownst to Team TRY3, the Branch Manager is doing this to obtain a god-like unit that was used against him years ago.