When Professor Xavier, the mentor of the X-Men, uncovers evidence of a planned secret alien invasion of Earth, he enlists the X-Men in a desperate race against time to find key pieces of technology to build a weapon powerful enough to stop the attacking forces.

Peter Parker, the amazing Spider-Man, has made an astonishing discovery-he has a sister! Unfortunately, a manipulative super-villain known as the Gentleman-who had a hand in the deaths of Peter's parents-has somehow brainwashed her into becoming the deadly supervilainess known as Pity! Together with Doctor Octopus, Electro, the Vulture, and Mysterio, they've formed the newest incarnation of the super-villain group dedicated to destroy Spider-Man, the Sinister Six! But there is something more than just the death of Spider-Man on the Sinister Six's agenda; something that has caused Col. Sean Morgan and his high-tech anti-espionage agents of S.A.F.E. to become involved. Spider-Man teams up with Morgan to stop the Sinister Six before they can put their world-threatening plan in motion, and to save his sister before it's too late!