Takato Matsuki is rather shy, but an ordinary schoolboy in fifth grade. Now he's crazy about "Digimon”. What he enjoys most is to play Digi-Battle card game with his friends or to sketch his own Digimon secretly in class. He’s the kind who could be anywhere. He is one of Digimon freaks, until one day he happens to gain a mysterious item, that changes his life. The strange blue card he’s never seen before turns out to be Blue Card. The moment his Card Reader reads data of Blue Card, the door to adventure opens in front of Takato. And then he encounters his fatal partner Guilmon. Now the new story begins.