Stark Enterprises has unleashed the Infinite Engine, which promises to be an energy source unlike anything ever seen before. But saboteurs from both A.I.M. and Hydra have set their sights on the engine as well—along with Dr. Doom. When a respected scientist is killed and the Engine taken over, Spiderman and Iron Man join forces to safeguard the Infinite Engine—and all of humanity.

The Mad Thinker, with the aid of the Red Ghost and his Super Apes, has hatched a worldwide conspiracy. He has placed lifelike duplicates of hundreds of key people throughout the world—including Reed Richards of the Fantastic Four! The remaining members of the Fantastic Four must work frantically to uncover the Thinker.