Tony Stark arrives in Japan with the aim of setting up the Arc Station in the first step in his World Peace Initiative. In front of all of Japan, he announces his new Iron Man model, Iron Man Dio, with himself in the pilot's seat. But during the demo, Dio crashes after a mysterious bug in the operating system.

The plutonium needed to prime the Arc Station is stolen and Tony must don the Iron Man armor and fight against Dio. The two Iron Men must fight to the death, with the fate of Japan hanging in the balance.