Yotsuya Yuusuke along with his classmates Shindou Iu and Hakozaki Kusue have been transported to a strange and unknown world inhabited by mythological creatures. As soon as they arrive, they meet somebody calling himself the Game Master who then grants them a time-limited quest. To aid them in this quest, he also bestows Shindou and Hakozaki with the roles of a Magician and a Warrior while Yotsuya is randomly granted the role of... a Farmer?!
This is how a hectic life of adventuring began for three students who now have no choice, but to complete random quests for several phases in the fantasy world if they want to stay alive and protect the real world from the demons and monsters they encounter.
This is the story of "Shinemon Nitta", the future manager of Card Capital.
10 years before the reunion of Aichi Sendou and Toshiki Kai, the card shop run by the Tokura family "Card Capital" was going out of business. Then came the attempt to take over the store by Esuka Hibino, the owner of a major card shop.
In order to protect Card Capital, Shinemon Nitta stands up as the "Self-proclaimed Manager!"
(Source: Cardfight!! Vanguard Wiki)
The anime centers on Hiiro Ryuugasaki, a student at Tensei Academy. Through a strange incident, Hiiro obtains a mysterious smartphone. The smartphone has installed the popular digital card game "Shadowverse." Through the game Hiiro meets rivals, participates in tournaments, and forms bonds with others.