Sitting in a cafe in Marrakesh, Peggy was watching an arms dealer. Spy, Super Soldier, Ageless. She’d been called many things, but none of them were who she was. Her name was almost entirely forgotten. She was just known as the Captain, since she couldn’t be Captain America, what with that English accent.
Howard Stark had done this to her. She was in her mid-forties, when someone tried to kill either her, or her godson Tony. To keep her alive, he had injected her with an experimental version of the serum, and it worked. When she awoke, she looked like she was 24 again, and in the best shape of her life. So, she did something with it.
She had been unreachable for weeks, following these dealers to their source, so she could destroy the weapons cache, and didn’t know what was going on back home. Had she bothered to answer her phone, she would find out that just after she left for this mission, a man was found in the ice, and that he was still alive.