Takato is a kid who is obsessed with Digimon (which is a hit TV show and card game). One night, a Digimon known as Guilmon (Takato's own creation) arrives in the real world, all with the help of a mysterious blue card.
He eventually meets two other children, Henry and Rika who also have their own partners (Terriermon and Renamon). They soon learn that their world is being invaded by out of control Digimon, all kept under the watchful eye of a mysterious man named Yamaki, who is a part of a mysterious government organization known as HYPNOS. With the aid of old friends and new allies, they embark on a journey to the Digital World to rescue Calumon, a mysterious Digimon. Their journey leads to the discovery of a new a sinister force that could devastate the Earth and the Digital World. Can the children become true Digimon-Tamers and save both worlds?