Action Man helps Knuck investigate his nephew Tom who has been involved in Gangrene's X-Vitamin steroid tests. Action Man tricks Dr. X into destroying Gangrene's lab and prevents him from putting the X-Vitamin into the city's water supply.
Soon after winning a martial arts match, Action Man encounters an assassin named Gem Eye. Learning they both have the same "AM" tattoo, Action Man is led to believe that he and Gem Eye are both members of an assassin cult called the Acolytes of Mayhem.
While Dr. X attempts to abduct the G7 leaders, Action Man is constantly troubled by how familiar Dr. X's plan feels. A memory flash reveals that it was Action Man himself that came up with the plan in the first place.
The Action Team head to Australia to free a group of locals being forced by Dr. X's to mine uranium, but Jet Extreme is shot down soon afterwards by Dr. X's Overseer robot. Stranded with no working equipment, Action Man and his friends must survive as Dr. X and the Overseer hunt them down.
Action Man and his team must protect a special fish called the "Puppet Quill" that can emit a special gas. Dr. X needs the fish to create a mind control gas which he plans to use on the world's leaders.
The people of Vulcana Island live in isolation from the rest of the world, but Dr. X earns the locals' trust after saving their island from a volcanic eruption, and manages to make the Action Team and the World Security Council look bad in the process.
Dr. X sends a diversionary attack to Brussels to keep the Action Team busy while he steals and arms a space shuttle from Cape Canaveral. His goal: to take over an abandoned but still armed space station.