Rogers receives a large back-pay reimbursement dating back to his disappearance at the end of World War II, and a government commission orders him to work directly for the U.S. government. Already troubled by the corruption he had encountered with the Nuke incident in New York City, where the gangster supervillain, The Kingpin, used his corrupted contacts in the US military to have the psychopathic test subject of a secret failed attempt to recreate Project Rebirth's body enhancements, Nuke, attack Hell's Kitchen in a murderous rampage to draw Daredevil out of hiding Rogers chooses instead to resign his identity, and then takes the alias of "the Captain". A replacement Captain America, John Walker, struggles to emulate Rogers' ideals until pressure from hidden enemies helps to drive Walker insane. Rogers returns to the Captain America identity while a recovered Walker becomes the U.S. Agent.