Six months after the D-Reaper was destroyed, the Tamers are planning to throw Rika a surprise party, but Rika finds out. Suddenly a train-Digimon named Locomon begins to race around the tracks, causing havoc. The Tamers respond to this, as Takato digivolves Guilmon into Growlmon to stop the train Digimon but fails as Takato, Rika and Renamon get on it in an attempt to slow it down. The others, excluding Suzie, use a freight train to catch up with Locomon

Omnimon confronts Mephistomon (who was formed from Apocalymon's data) in a dark corner of the Digital World over Mephistomon's attempt to destroy both the Digital World and the Real World and incorporate the data in order to become truly invincible. They fight, but then Mephistomon sees a chance and slips into the Real World.