Keito Matsuda (voiced by Makoto Tsumura) is a fifth-grade boy who loves fantasy. By chance, Keito picked up a magical card that took Keito to the digital world where Digimon lived. There, Keito met Guilmon. At this time, he didn't know that Guilmon would be the most important partner and friend in his life. In order to protect the digital world and Digimon, Suzakumon, one of the Four Holy Beasts, continuously sent the emperor demons to the human world, causing danger and chaos. Keito and his friends Makino Ruki (voiced by Fumiko Orikasa) and Li Jianliang (voiced by Mayumi Yamaguchi) joined the battle to protect peace. Not only that, Suzakumon also took away Guramon, who holds the key to the evolution of Digimon. Following Guramon's trail, Keito and his group broke into the digital world and embarked on a great adventure.