Diaboromon hacks the Pentagon's computers and launches the Peace Keeper to Tokyo Bay, specifically near Tai's neighborhood, intending to eliminate the DigiDestined.
In the English dub, Diaboromon launches a second missile headed to Colorado, likely meant for Willis.
Diaboromon then starts a countdown and creates thousands of copies of himself, challenging the DigiDestined to find which one has the clock that controls the missile's detonation.
In the Japanese version, Tai and Izzy are warned about the missile by a Taiwanese middle school student who hacked the Pentagon, while in the English dub they are told about it by Willis.
Omnimon eventually destroys Diaboromon's clock, preventing the missile's explosion just as it falls in Tokyo Bay.
Notes and references
↑Digimon Adventure: Our War Game! (Japanese version) Izzy: "There's one missile, codename Peace Keeper. Range of 20000 km, that's pretty much the entire Earth. Max speed of 15000 mph." / Tai: "Um, what's that in kilometers?" / Izzy: "Parentheses, Mach 23."