During a training combat simulation, Captain America notices his muscles are cramping and his coordination is slightly off. His session is interrupted by the arrival of Dr. Kincaid, bearing bad news. Cap’s lab tests show that his body is experiencing negative side effects from his Super-Soldier Serum; the prognosis: if Cap keeps up the intense activity of his hero activities he will be completely paralyzed in a year. If he retires immediately, he will probably maintain normal mobility for the rest of his life. Cap swears the doctor to secrecy and tries to deal with his anger and frustration….
At the same time, a man dressed as Captain America enters a bar and buys a round for the house, getting nasty with a patron who tries to pick a fight with him, forcing the tough to lick his boots….
At his Brooklyn Heights headquarters, Steve Rogers confides in his girlfriend Rachel Leighton a/k/a Diamondback about the dilemma facing him. She suggest a fun night out to seize an opportunity they may not have for long….
Later the Captain America impostor shows up at a fundraiser for mayoral candidate Rudolph Bradley, accompanied by a hot but trashy date. "Cap" displays a lot of cynical arrogance, surprising the guests. The villain known as the Porcupine suddenly bursts in, bent on revenge against Cap. Refusing to take the fight outside, Cap brawls with the baddie, leading to several onlookers being injured, including the candidate and his wife….
Steve and Rachel meanwhile, are at a sidewalk café, when a young shoplifter dashes by. Steve nabs the boy and discovers he was stealing comic books including an issue of CAPTAIN AMERICA. Questioning the young thief about the lessons he learns from comic books Steve is surprised when the kid says he doesn’t read the books, he just sells them for a profit. Steve is further disheartened when the comic shop owner shows a preference for violent vigilante heroes like the Punisher and Wolverine, leading Steve to think it might be best for him to retire his outdated values. Steve gets an emergency call from Peggy Carter telling him that Cap was seen battling the Porcupine. Knowing it was an impostor (and that the Porcupine is dead), Steve heads over to investigate, accompanied by Rachel. At the hotel they find a scene of pandemonium, with the crowd believing that Cap has gone rogue….
Cap schedules a press conference to address the issue at Avengers Mansion the following afternoon, partly as a trap for the real villain. As he explains to the assembled reporters that he was framed by an impostor, the crowd is attacked by the original Masters of Evil (Baron Zemo, the Executioner, the Black Knight, and the Melter) who are all dead. Hearing Cap’s troubled reaction, Diamondback and the Avengers (Black Widow, Vision and the Black Knight) rush to his aid but do not see any villains. As the journalists begin to suspect Cap has gone mad, a costumed figure steps out of the woods with the unconscious Mirage, master of illusions. Introducing himself as Super-Patriot, he announces he will replace the incompetent Captain America, then takes his leave. Diamondback follows him but soon loses the "hero" downtown. As the press conference fizzles out, Black Widow loses Mirage, whom she was guarding. Security tapes show that "Mirage" morphed into the Purple Man and commanded Widow to let him leave. Cap now knows they are facing an adversary who can assume the form and powers of dead criminals. [A few blocks away, Super-Patriot meets up with his partner; Operation: Smear is a complete success.] Meanwhile, Cap tells Diamond that he doesn’t know what he is going to do: "the harder I fight, the faster I lose everything."