A fourteen-year-old youth named Marcus Damon, who desires to be the best fighter in the world, meets a strange dinosaur-like creature and engages the creature in a fist fight that ends in a draw. At that time, after introducing himself, Agumon vows to be Marcus's follower as the two are confronted by Yoshino Fujieda, a teenaged member of a government agency known as DATS dispatched to capture Agumon. After escaping and hiding Agumon in Tokyo Tower, Marcus is found by Yoshino who brings him to her superior Commander Sampson. Commander Sampson and his Digimon Kudamon explain to Marcus that Agumon is a wild creature that will go out of control. Though Marcus dismisses this with the intent to bear any responsibility for anything Agumon does wrong, an alarm of a burger joint being attacked is reported in the area Agumon was hidden in. Though it appeared Agumon was the cause, it turned out to be the work of a Kokatorimon. After Kokatorimon knocks Agumon out, a furious Marcus sprints towards Kokatorimon and punches the bird in the face. Astonished of the energy generated from his fist, Marcus encounters a mysterious old fisherman who gives him a Digivice to channel his charged DNA in so Agumon can become stronger. This causes Agumon to Digivolve into GeoGreymon, defeating Kokatorimon as it reverts him into a DigiEgg. Commander Sampson is impressed by the turn of events.