Tony Stark faces a new generation of threat when an old scientific project gives rise to Extremis, a technology capable of radically altering the human body. When a man transformed by the process becomes almost impossible to stop, Iron Man realizes that his traditional armor is no longer enough. With the help of scientist Maya Hansen, Tony investigates the origins of Extremis while questioning the future of his own technology and his place in a world where humanity and machines are becoming increasingly connected. Faced with an opponent who is faster, stronger, and biologically enhanced, he must consider changing himself in order to keep protecting others.