SON OF M told how Quicksilver stole the precious Terrigen Mists from the Inhumans and how Black Bolt retaliated by declaring war on humanity. Now that war is about to break loose as Gorgon leads a terrorist attack on New York. Old friends become deadly enemies when the Fantastic Four are forced to defend their city against the Inhumans.

Gorgon and three other inhumans go to Earth to make a statement that would let the people of the world know that the American government has basically stolen their property (the Terrigen Mists). One of the inhumans gets a little excited and kills an opera house full of wealthy and influential people. The Inhumans leave but are captured by the Fantastic Four before they can escape. The Inhumans are taken to a O.N.E. base where Gorgon is further mutated by a second exposure to the mists.