Warning: This article contains SPOILERS for Avengers: Endgame.
Avengers: Endgame has quite a few major plot holes. The culmination of 11 years' worth of Marvel blockbusters, Avengers: Endgame has broken practically every box office record going. But that doesn't mean Avengers: Endgame is faultless; it has a significant number of plot holes. There's a sense in which that was inevitable, given it had to achieve so much.
It was something of a victory lap for Marvel, using time travel in Avengers: Endgame to revisit key moments in the MCU's history, undo Thanos' victory in Avengers: Infinity War, and ultimately feature every superhero ever seen in the MCU. It was jam-packed with Easter eggs, and even managed to fix plot holes in previous films along the way.
Given Avengers: Endgame was so ambitious, it's frankly no surprise that the plot has some significant problems. Ironically, in some cases these problems are being amplified by the directors - Anthony and Joe Russo - who are attempting to answer fan questions, but are instead muddying the waters.
Doctor Strange's Endgame Plan Is Insane
The most problematic plot hole is the simple fact that Doctor Strange's entire Endgame plan doesn't make any sense at all. In Avengers: Infinity War, Strange explored 14,000,605 different possible outcomes in the battle against Thanos, and he identified only one in which the heroes triumphed. He then chose to hand over the Time Stone to Thanos at a carefully chosen moment, insisting there was no other way. Presumably Strange's timing was based on the need for Scott Lang to be stranded in the Quantum Realm when Thanos snapped his fingers, and for Tony Stark to stay alive in order to ultimately snap his fingers.
But here's the problem; Doctor Strange's Endgame plan is predicated on random chance. Firstly, it requires a rat to run across the controls of the Quantum Tunnel in just the right way to free Scott from the Quantum Realm; if that hadn't happened, the Avengers would never have hit upon their time travel plan in the first place, and the snap would never have been undone. Incredibly, the Russos have actually suggested that Strange did indeed view timelines in which the rat hadn't run over those controls at all. So Strange literally gambled the fate of half the lives in the universe on the chance of a rat's feet happening to knock the right buttons and switches.
It gets even crazier. The final battle in Avengers: Endgame was an outright war between the assembled heroes and the armies of Thanos. In that scenario, any one action could have changed the flow of events. If a gunner in Thanos' Sanctuary II craft had happened to aim slightly differently and knocked Tony Stark a little bit further away from Thanos, then the Mad Titan would have won. If Tony had just slipped in the mud as he was rushing to intercept Thanos, then all of reality would have been rewritten. The truth is that Doctor Strange's 1-in-14,000,605 victory was simply a matter of dumb luck.
How Does Time Travel Work In Avengers: Endgame?
The vast majority of time travel films make absolutely no sense when you take a step back and think about them, and Avengers: Endgame is no different. The Hulk opens with an explanation in which the past and the future form a sort of loop, meaning it's impossible to rewrite history; if you travel back in time, then the future becomes your past, and therefore cannot be changed. It's roughly in accordance with modern quantum theories - which are then abandoned. The Ancient One modifies the idea to suggest that removing an Infinity Stone creates an alternate timeline; the Avengers need to return them in order to cauterize that timeline. And then, in another twist, at the end Captain America travels back to the past to live out his life with his beloved Peggy Carter. Has he been living in the background of the MCU all this time? Or did his traveling back create another alternate reality? The film is silent on this point, perhaps intentionally so.
The Russo brothers have attempted to explain all this in a Q&A (via QQ), with Joe Russo giving a very different account of time travel to the Hulk and the Ancient One. "If you go back to the past, you simply create a new reality," he explained. "The characters in this movie created new timelines when they went back to the past, but it had no effect to the prime universe. What happened in the past 22 movies was still canon." That's why War Machine can interrupt the opening scenes of Guardians of the Galaxy by knocking out Star-Lord, because his presence there has created a whole new timeline. It's the Thanos from this new timeline who pursues the Avengers forward in time, and is then killed, explaining why the prime timeline's Thanos still happened. By the same logic, Steve Rogers has created a new timeline by going back to be with Peggy Carter. At the end of Avengers: Endgame, he somehow makes the jump from this timeline back to the prime one in order to give Sam a shield.
This explanation just about makes sense, but it doesn't match at all with the time travel theories established in the film itself. It also doesn't explain why the Avengers return the Infinity Stones; according to Joe Russo's account, Cap traveling back in time to return them should just create even more alternate timelines. All in all, the truth is that Avengers: Endgame is no more consistent in its time travel than any of the other films it actually pokes fun at.
Why Didn't The Avengers Go Back To The 1970s To Begin With?
One important sub-plot is that the Avengers are running short of Pym Particles, meaning they can make a limited number of trips to the past. So why didn't they break their time heist down into two phases; the first, a mission to raid history to obtain as many Pym Particles as possible, and the second to then travel around the timeline collecting Infinity Stones? The best solution here is that the Avengers wanted to get on with it. They're mission-focused, and it's only when things start to go wrong that they realize it might be a good idea to get some more Pym Particles.
Where Does Ant-Man Keep Getting His Pym Particles From?
The limited number of Pym Particles causes another issue, though; the fact that Ant-Man keeps size-changing. The Avengers are very specific about each member of the team having just enough Pym Particles to make their essential jumps through the Quantum Realm - and yet they hatch a plan to obtain the Tesseract that involves Scott Lang using another batch to shrink down and damage Stark's Arc Reactor. Even more strangely, when Thanos attacks the Avengers Compound Scott suddenly has the Pym Particles he needs to shrink in order to survive the blast; and he then has another set handy with which to turn into Giant-Man. He uses more Pym Particles over the course of the film than the Avengers claim to have.
Presumably the Avengers felt sabotaging the Arc Reactor was the only way to get to the Tesseract, given it would be under the guard of Thor until he left Earth. So they accepted that they'd have to use an extra vial, and didn't count it when they handed out the Pym Particles. The rest may have been given to Scott off-screen by Captain America, who was shown picking up extra batches of Pym Particles when he raided Hank Pym's lab.
How Was It So Easy To Extract The Aether?
A major plot point in Thor: The Dark World is that even the Asgardians don't know how to safely remove the Aether from Jane Foster; only the Dark Elves can do it. It's why Thor takes Jane to Svartalfheim; he plans to give Malekith a chance to extract the Aether, and then attack once Jane is safe and the Aether is vulnerable. Somehow, though, in Avengers: Endgame the Avengers are able to put together a simple device to draw the Aether out of Jane. They manage to do it on the basis of Thor's rambling descriptions, and without even having the Aether to hand to experiment on. They're really lucky it worked.
How Does Steve Rogers Return the Tesseract?
Avengers: Infinity War made it clear that the Tesseract is essentially a container for the Space Stone. Presumably the Avengers broke it open just like Thanos in order to insert the Space Stone into their own Infinity Gauntlet; but that raises the curious question of just how Steve Rogers returned it at the end of the film. Perhaps he simply dropped off the Space Stone instead, creating a new timeline where a bemused S.H.I.E.L.D. found the Tesseract mysteriously transformed into an Infinity Stone all the way back in 1970.
Where Does Captain America Get The Shield He Gives To Falcon?
The elderly Captain America is keen to pass on his shield to Falcon as the next Captain America. It's a touching and powerful moment, lifted straight from the comics, but it's also pretty problematic. Where did Steve Rogers get the shield from in the first place? His shield was shattered beyond any possible repair during the battle with Thanos.
There are really three possible explanations for this. The first is that the Wakandans could've made Captain America a replacement shield, and that's the one he's handing over. The second is based on an Easter egg in Spider-Man: Homecoming, in which Happy Hogan was putting together an inventory of items he was moving from Avengers Tower to the Avengers Compound; they included "Cap's new shield," suggesting Tony was working on another shield before the events of Captain America: Civil War. Perhaps Sam has been given this shield, rather than the original. Finally, if Steve Rogers does indeed now live in a parallel timeline, then perhaps he's taken the shield from that universe's Captain America. It's impossible to say which of these is true.
How Powerful Is Stormbreaker?
In Avengers: Infinity War, Stormbreaker was designed to be the ultimate Thanos-killing weapon. It had the power to summon the Bifrost, which can potentially be used to tear entire worlds apart; it could even resist a concentrated energy blast from all six Infinity Stones. Then, in Avengers: Endgame, it can be held at bay by Thanos' sword with apparent ease. There seems to be a remarkable disparity in terms of the ax's power levels in the two films. Essentially, Stormbreaker is as powerful as the plot requires it to be at that given moment.
How Was Laura Barton's Phone Still Working?
One final, minor, and frankly rather amusing, plot hole is, how does Laura Barton's phone work five years after she last paid the bill? When the Avengers succeed in undoing the snap, Laura immediately grabs her mobile and gives her husband a call. The problem is, though, that she's been gone for five years. That phone really shouldn't have been working.
- Spider-Man: Far From Home (2019) release date: Jul 02, 2019