The upcoming '90s-set superhero origin story Captain Marvel may create a plot hole in The Avengers, a movie in which Nick Fury claimed that Thor was the first alien S.H.I.E.L.D. had encountered on Earth. If so, it's a perfect example of one of the biggest challenges of the shared universe model: trying to maintain a consistent timeline amid an ever-more complex map of movies and TV shows.

That's particularly the case with Captain Marvel. Set in 1995, this film is essentially a prequel to the entire Marvel Cinematic Universe. It features an early adventure of Samuel L. Jackson's Nick Fury and Clark Gregg's Phil Coulson, and is expected to explain just why Fury became a firm believer in the Avengers Initiative. There are explicit ties to the Guardians of the Galaxy movies as well, with Lee Pace reprising the role of Ronan the Accuser and Djimon Hounsou returning as Korath the Pursuer. It even looks as though the film will involves the Tesseract.

Related: The Tesseract Has Appeared In More Marvel Movies Than Captain America

All that means Captain Marvel is the biggest retcon the MCU has ever attempted. It will shine a whole new light on some of the MCU's most important characters (and potentially even upon the Infinity Stones themselves, if new information is revealed about the Tesseract). But how well does this retcon sit with the MCU as we know it?

Thor Was The MCU's First Alien (Until Captain Marvel)

The core problem is that, until Captain Marvel, the MCU had consistently argued that S.H.I.E.L.D. didn't know about the existence of aliens until they crossed paths with Thor in New Mexico. In one scene in The Avengers, Nick Fury claimed that Thor's arrival on Earth was an absolute game-changer for the organization. "Last year, Earth had a visitor from another planet," he explained, "who had a grudge match that leveled a small town. We learned that not only are we not alone, but we are hopelessly, hilariously outgunned." The existence of life on other worlds had been proven, S.H.I.E.L.D. now knew that alien technology was far in advance of our own, and aliens had their own agendas and feuds that could be dangerous for any humans who crossed their paths.

Fury is explicitly claiming that the Asgardians were the first aliens S.H.I.E.L.D. had (at least knowingly) encountered. Interestingly, the wider MCU has been careful never to contradict this; although Agents of S.H.I.E.L.D. revealed Fury had acquired a blue-skinned corpse, that alien was long dead and none of its technology was preserved with the body. When Coulson encountered Sif, he asked her about these blue-skinned races, and didn't react at all when she listed the various species out there - including the Kree. As far as the MCU is concerned, then, up until now Thor has been seen as the first time S.H.I.E.L.D. encountered a living alien - and the first time they discovered how dangerous extraterrestrial weapons could be.

Nick Fury Blames Thor For S.H.I.E.L.D.'s Weapons

Supporting this assertion, Nick Fury claimed that S.H.I.E.L.D.'s priorities were changed in the wake of New Mexico. The World Council's response to the Thor incident was to demand S.H.I.E.L.D. find a way to level the playing field as quickly as possible, and so S.H.I.E.L.D. began pursuing advanced technology. The Tesseract Project became an absolute priority; during World War II, Hydra proved that the Tesseract's power could be used to create dangerous energy weapons. What's more, legends tied the Tesseract to Odin himself, suggesting this was an Asgardian power source. Tesseract technology became a major strategic priority. Meanwhile, although it's never directly addressed on the big screen, S.H.I.E.L.D. scientists also began working on the abandoned body of the Destroyer. According to the tie-ins, they took it apart and worked out how to reverse-engineer its energy weapon. The prototype gun was the weapon used by Coulson in his clash with Loki on the Helicarrier in The Avengers; it returned in Agents of S.H.I.E.L.D.'s season 1 finale.

Related: A Complete History Of The Marvel Cinematic Universe

Tie-in comics have suggested that Fury believed all these different projects were just distractions from his most important agenda, which he was struggling to get the World Council to sign off on. Fury believed the Avengers Initiative was Earth's last, best defense. He viewed the Tesseract project and the Destroyer experiments as little more than backup plans, to be used in the event the Avengers failed.

Until now, then, Fury has consistently claimed that the first aliens S.H.I.E.L.D. encountered were Thor and the Asgardians. The organisation's strategic priorities have strongly supported this statement, suggesting he was telling the truth.

Page 2 of 2: Captain Marvel (Seems To) Create An Avengers Plot Hole

Captain Marvel (Seems To) Create An Avengers Plot Hole

But Captain Marvel changes everything. It reveals that Nick Fury encountered his first aliens way back in 1995. And not just any aliens, either; he crosses paths with both the Kree and the Skrulls, two galactic empires with advanced technology and powerful weapons. In the case of the Skrulls, Fury discovers alien shapeshifters who can use their powers to infiltrate and compromise Earth's government and power-structures; it's already been confirmed that the war-leader, Talos, has replaced Fury's boss. What's more, the trailers even seem to suggest that Fury will learn just how powerful these two alien races really are. There's one scene in which Fury and Captain Marvel steal a S.H.I.E.L.D. Quinjet from Project P.E.G.A.S.U.S. Significantly, the trailers show what may well be that same Quinjet heading into space to dock with a cloaked alien spacecraft. By the end of the film, Captain Marvel has had a significant power-up, and there's a full-scale battle in space. Let's face it; over the course of Captain Marvel, Fury will learn that aliens exist and also get a sense of just how powerful and dangerous they can be.

This raises two difficult questions. Firstly, why does Fury wait so long before he begins to prepare a defense for the Earth? He only seems to have prioritized the Avengers Initiative after Tony Stark outed himself as Iron Man, and even then he doesn't appear to have been in much of a hurry about it. Nor does he seem to have begun the process of upping S.H.I.E.L.D.'s technology until after the encounter with Thor in New Mexico. So Fury's inaction seems rather odd. Secondly, why did he lie to the Avengers and claim that Thor's arrival was such a game-changer?

Related: Captain Marvel Trailer Easter Egg Reveals Infinity Stone Connection

How Can This Plot Hole Be Fixed?

Let's first acknowledge that Nick Fury is the world's premiere super-spy; as Tony Stark acknowledged in The Avengers, "Even his secrets have secrets." By his own admission, Fury has serious trust issues, and he prefers to keep his cards close to his chest. This reluctance to trust others is probably rooted in the events of Captain Marvel, a film where his superior officer at the time was replaced by a Skrull impostor. What's more, it looks as though that experience will cost Fury dearly; it's already been confirmed that Captain Marvel will explain how he lost an eye, and according to Fury himself that was the last time he trusted anyone.

So here's the as-yet-unanswered question: While Fury knows about the Skrulls, the Kree, and Captain Marvel, do his S.H.I.E.L.D. bosses? The most explosive cosmic action in Captain Marvel appears to take place in orbit, and back in 1995 Earth's satellite systems weren't quite so effective as they are today; it's possible nobody realized a battle had been fought in space. More importantly, there's no reason to assume Fury reported what had really happened to his superiors. His own commanding officer had proven to be a Skrull impostor, after all, so perhaps he feared there could be more out there. Or perhaps he was just naturally reluctant to confide the world-shaking truth. Whatever the case, if Fury didn't tell S.H.I.E.L.D. about the Skrull and the Kree back in 1995, it would put him in a difficult spot as he rose through the ranks. However much he wanted to prioritize defending the planet - predominantly through the Avengers Initiative - the World Council wouldn't share his agenda. The only way he could get them on-side would be to admit that he'd been deceiving S.H.I.E.L.D. for years, and that would risk his position.

That would neatly explain why S.H.I.E.L.D.'s priorities changed after the events of Thor. This was an undeniable case of first contact, with the grudge match between Thor and the Destroyer fought in an American town. Although Fury managed to cover it up as far as the public were concerned, he had to use a considerable amount of S.H.I.E.L.D. resources to do so, and there was no hiding it from the World Council. But, according to the official tie-in comic Fury's Big Week, the World Council was never really persuaded by the Avengers Initiative; they were much more interested in proven technology like the Tesseract Project. With the Tesseract now active - and tied to the Asgardians by legend - they wanted S.H.I.E.L.D. to finally develop those Hydra-style Tesseract weapons.

This explanation fits perfectly with Fury's lie to Thor. He has concealed the truth about the Kree and the Skrulls from S.H.I.E.L.D. since 1995, and even the likes of Maria Hill and Black Widow don't know about his adventures with Captain Marvel. As far as S.H.I.E.L.D. is concerned, the New Mexico incident was the first time they'd encountered aliens, so Fury's lie in The Avengers was more of a half-truth than an outright falsehood. And the S.H.I.E.L.D. Director has no reason whatsoever to complicate matters by tossing in a mention of the Kree and the Skrulls, in the middle of dealing with the threat of Loki.

More: MCU Theory: Guardians of the Galaxy's Missions Are All Captain Marvel's Fault

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