Background: For years the secret spy agency known as S.H.I.E.L.D.
(Strategic Homeland Intervention Enforcement and Logistics Division) worked from the shadows to protect all humanity against terrorists successfully avoiding attacks and wars.
When aliens descend upon New York City SHIELD calls in special individuals to fight back the extraterrestrial enemy. These individuals are the Avengers – billionaire Tony Stark a.k.a.
Iron Man, the sweetheart scientist Bruce Banner who turns into the green raging monster known as the Hulk, revived national hero Captain America a.k.a.
Steve Rogers, legendary Norse god Thor and two of SHIELD's finest agents, Natasha Romanov a.k.a. Black Widow and Clint Barton a.k.a. Hawkeye.
After New York the world not only learned of the existence of aliens, but the agency was now revealed. This didn't stop them to continue operating, albeit a little trickier than before.
Most agents had several aliases to keep their identity a secret. Many of them were often send on covert missions.
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