The following contains spoilers for Captain America: Sentinel of Liberty #2, on sale now from Marvel Comics.

Captain America's shield has long been an American symbol, and a symbol of the character himself. But Captain America: Sentinel of Liberty has postulated Cap's shield might not exactly be made in America -- in fact, its origins surprisingly might not even be of this world.

Captain America: Sentinel of Liberty #2, by Jackson Lanzing, Collin Kelly, Carmen Carnero, Nolan Woodard and VC's Joe Caramagna, reveals Cap's shield possibly has an extraterrestrial -- and sinister -- genesis. After battling and overcoming a collective of fighters defending a German installation known as The Forge, Cap looks up to see a startling sight: a large UFO bearing a design similar to that of his shield on its underside -- a craft that's decidedly unfriendly.

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captain america first sees ufo looking like his shield

The spacecraft goes on to launch a metallic, alien-looking fighter of its own against Cap, but the outcome remains unknown, until presumably next issue. The alien aggressor is dispatched by a mysterious enclave of five entities -- known as The Machine, The Money, The Power, Love and The Revolution -- voting to "redact" either the shield, Cap himself, or both.

"It's not your symbol -- it's theirs," is the mantra repeated throughout the series. Cap first heard the phrase last issue after he and The Winter Soldier defeat a terrorist attacking New York City's 4th of July parade -- one garbed in the costume of their old World War II ally, The Destroyer. The individual posing as The Destroyer is discovered to merely be a pawn, however, and is subsequently killed remotely, leaving Cap with the mystery of the enclave behind the attack -- and the meaning of those cryptic words.

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Cap is already unraveling some clues, though, thanks to his old allies and ham radio aficionado pals. The so-called "Radio Company” has deciphered several coded messages broadcast over the airwaves -- one of them referencing the mysterious Forge. The opening moments of the series' first issue revealed The Forge was where Cap's legendary round shield was first manufactured, but its connection to the enclave controlling the UFO bearing the shield's markings remains unknown.

The origin of Cap’s shield has expanded throughout the decades. First conceived with a more triangular design by Joe Simon and Jack Kirby in 1941’s Captain America Comics #1, it was later changed into its better-known circular shape. Its properties have also changed over the years -- originally simply made from common metals and potentially replaceable, it’s now known to consist of Adamantium, Vibranium and possibly other rare metals, and is functionally indestructible.

Captain America: Sentinel of Liberty #2 is now on sale from Marvel Comics.

Source: Marvel Comics