Spring break turns into a summer war when the evil Diaboromon wreaks havoc on the internet, and Tai and Matt must achieve a new Digivolution to defeat him! Will Tai and the Digidestined save the world, and will Sora ever forgive Tai for giving her a hair clip?

After the older DigiDestined are abducted by the mysterious Kokomon, the next generation of kids team up with American DigiDestined Willis to rescue them - only to discover that their enigmatic enemy has an unexpected connection to their new friend!

The DigiDestined go up against Diaboromon again. Tai and Matt head back to the Internet to deal with him with Omnimon, while the younger Chosen Children go to deal with the rampage of a swarm of Kuramon (Diaboromon's Fresh form). With the help of Angemon and Angewomon (with T.K. and Kari), Omnimon was able to destroy Diaboromon again, but it turned out to be a trap, as his destruction allowed many more Kuramon to go to the Real World. Things go out of control when the Kuramon in the Real World merge to create a Mega level called Armageddemon, an alternate Mega in Diaboromon's evolutionary line. It is so powerful that neither Omnimon nor Imperialdramon were able to defeat it on their own.

This movie is an alternative version of the TV series; it is composed of the two 2007 OVAs, edited to improve the pacing of the plot, and an extra segment akin to a TV episode where the cast are given the task of studying flowers. The plot has several differences to the TV series, most important being Sirius's death at the beginning, Apollo's different childhood and the more marked focus on the events of 12000 years ago, particularly Apollonius' death and Reika's previous incarnation's involvement.