The Time Travel and Ending of “Edge of Tomorrow” Explained

June 6, 2014


Last night, I went to see the new Tom Cruise and Emily Blunt science-fiction film Edge of Tomorrow, which is based on the Japanese manga All You Need Is Kill.

The racial cross-casting of Cage’s character — he is inspired by Japanese protagonist Keichi in the manga — aside, this film is phenomenal. Nerds and feminists — and especially nerd feminists — will adore this movie. It’s sharp, funny, entertaining, compelling, and visually stunning. Haters of Tom Cruise get to see Tom Cruise get killed about a hundred times in stunt scenes that Cruise himself described as “channeling Wile E. Coyote” on Daily Show last night. Emily Blunt’s Rita is stellar: she is the aspirational super-soldier, and not the simpering girlfriend; she’s also got a bad-ass giant sword. Those who loved Pacific Rim‘s portrayal of a male-female peer relationship that was largely non-sexual will adore the relationship between Rita and Cruise’s Cage in this film.

Basically, it’s just really good. Go see it. I’ll wait.

Okay, now that you’ve seen it — did you have all kinds of thoughts and questions about those aliens and the “time travel” in this movie? Snoopy and I did, too, and we geeked out over a late-night dinner about the science of how what happened could have happened. Here’s what we came up with, and I’m posting about it because — goshdarn it — I think we really figured this thing out.

Spoilers! This post will spoil the entire movie.


Okay, so the conceit of the film is that these aliens, called Mimics, have a looping “time travel”-like power that allows them to reset a day, memories intact, whenever they are in danger. That power gets transferred to Cruise’s Cage, setting the whole film off. All You Need Is Kill has a similar conceit, but from the manga’s Wikipedia page, other aspects of the Mimics seem different than those of Edge of Tomorrow. So this post is going to treat the Edge of Tomorrow Mimics as if they are stand-alone.

The “time travel” of the Edge of Tomorrow Mimics isn’t really time travel, it’s consciousness-travelling (similar to the conceit of the travesty that was X-Men: Days of Future Past): the Mimics — and by extension Cage — are not physically travelling from one timepoint to another; instead, their minds are jumping backwards to an earlier timepoint, allowing them to alter the course of time by making decisions informed by a possible future.

But, how does this really work? What is the relative role of the Alphas (the glowing sentinel Mimics) and the Omega (the central core that Snoopy thought was heavily inspired by Starship Troopers‘ Brain Bug)? And, isn’t this just one giant incubator for alternative universes? (To that last point, the answer is yes.)


There are two clues: 1) the Mimics are actually a single organism with each individual Mimic type acting in tandem with the whole, and 2) the “resetting” power always bringing Cage back to the same point in time. The key is to think about the Mimics not as some evil, super-intelligent being; instead, think of it as a creature acting purely on instinct. Think of it like biology.

The Mimic is an organism whose sole purpose is to conquer planets, and has evolved a complex self-defense mechanism to ensure its own propagation. The Mimic drones are the “claws” — the Mimics’ primary defense system. The Alphas are “sentinels” that exist to gauge the degree to which any threat makes it past the drones; if something kills an Alpha, this indicates sufficient danger to instinctively trigger the Mimics’ final self-defense mechanism: the looping.

And how does that work? In addition to its primary function to coordinate the actions of all drones and Alphas, the Omega has an additional characteristic. The Omega Mimic exists simultaneously at three points in time. If you think of time as a linear dimension, each of us occupies a single point on that line. The Omega Mimic exists instead as a line connecting three points spanning an approximate 48 hour period: the “distant past”, the “present-past”, and the “future-present”. The “present-past” point serves as the main anchor point: a fixed position in time from which to (routinely) reset the day. From that point in time, the Omega extends a version of itself towards the “future-present” like a cell that moves by extending a tendril ahead to test a space out to see if it’s safe.

A macrophage extends a "foot" out into space to "test the waters" before moving its entire body to the new position.
A macrophage extends a “foot” out into space to “test the waters” before moving its entire body to the new position.

And, like cells, if the Omega encounters danger in that future (as evidenced by the death of an alpha) it instinctively retracts back to its first anchor point and tries going in a different direction.

And what about the “distant past”? That’s a reserve anchor point that allows the Omega to reset from even farther back in time, allowing it to never be fully committed to a single temporal direction. If things get really dicey, it will retract far enough away to move in a completely different direction, entirely. If we think of it spatially, the “present-past” and “future-present” are like taking steps after deciding to go left; the “distant-past” exists as a mechanism to abandon going left entirely.

So how did Cage get the power to loop? Well, the Alphas are “sentinels”: as deadly as a drone, but their true power lies in their blood. If the looping power is a final self-defense mechanism for the Mimics, than the death of an Alpha would be the trigger to initiate a reset. Mixture of Cage’s blood with a dying Alpha (somehow — this is never explained and defies biology) integrated Cage into the Mimic’s  network of sentinel Alphas. In essence, as far as the Omega was concerned, he was another Alpha. Every time Cage died, the Omega mistook this for a signal that it was in danger and triggered a loop.

Cage was never in control of the looping power. The Omega was being fooled into looping by thinking Cage was an endlessly dying Alpha sentinel.


Update: (I solidified this particular detail after this post was written, so am adding it now). The “time travel”, specifically, is psychic-based and is channeled through the Omega. Basically, when the Omega is given a signal to loop, it pulls a clone or mirror of all the memories of all its network of itself and its Alphas (probably not the drones, that’s huge amount of processing for limited gain) and creates a copy of those memories in the Omega. Then, it sends that entire data package through itself to the “present past” anchor point, and then redistributes those memories out to the Mimic network (and to Cage, who is a pseudo-Alpha). From the perspective of an Alpha, this would appear to be like you just traveled back in time, but really you just got all the memories and life experiences of a future Cage who made different choices.

So, why did the Mimics send him to the dam and why didn’t they try to kill him when he was there? Well, an organism that evolves such a complex self-defense mechanism will also likely have a mechanism for repairing problems when they arise. In this case, this “time travel” self-defense mechanism has one serious flaw: it would trap the Omega in a perpetual loop if there were an Alpha that was weak or broken, endlessly throwing itself into harm’s way when there isn’t sufficient danger to warrant a “reboot”. There needs to be a self-repair mechanism for the Mimics to identify and correct such a problem.

The visions seen by Rita, and then later by Cage, were intermixed with their own memories (hence Cage sees the dam just as he reboots), and it is this repair system taking effect: the Omega sent a specific signal that would attract Alphas to a single location, where they could be safely disposed of far away from the location of the Omega itself  (this is to keep the Omega safe in case the defective alpha is dangerous). When Cage arrived at the dam, the drone and the Alpha stopped Cage from killing himself because they don’t want to loop again, since the whole point of the mechanism is to stop unnecessary looping. It’s unclear what they would’ve done to Cage if he hadn’t killed himself, but most likely if he had been an actual Mimic, they would have removed him from the “sentinel” network by performing a process similar to the blood transfusion, and then killed him. That’s why the Alpha wounded him, but didn’t kill him.

So what about that ending?

After a blood transfusion, Cage is essentially excised from the Alpha network, no longer being mistaken by the Omega as a “sentinel”. And then stuff happens and he kills the Omega by dropping a bunch of grenades into it. But then he wakes up in the helicopter at the start of the film and all is right with the world?

Well, at the moment of his death, Cage’s blood mixes with that of an Alpha, and he temporarily becomes a pseudo-Alpha again, which allows him to retain his memories in the reboot. Meanwhile, because the Omega was itself dying, one final loop was triggered by the Omega in a final desperate attempt to escape danger. The Omega looped not to the “present-past” point but to the “distant past” anchor point since the Omega itself wanted to escape an imminent threat to its core. Because of the Alpha’s blood, Cage went along for the ride and woke up with the Omega at the “distant past” timepoint.

But, since the Omega exists at multiple points in time (rather than a single moving point) and was actually killed in the “future-present”, the explosion actually rippled back in time and killed the Omega at all the other time points, too. So, when Cage wakes up, he wakes up at the “distant-past” anchor point along with his memories at the precise position in time that the Omega kept anchored to in reserve, and when it blows up. This allows for the lovely ending where everyone we watched die horrifically in the movie get to live again in blissful ignorance.

And does Cage now have time-traveling powers? Is he immortal? No. Being an Alpha only ever meant he was a sentinel, invoking the looping powers of the Omega upon every death. He could never himself loop. With the Omega dead, Cage is back to being a normal dude with one final lease on life.

So, what do you think? Does this make sense? Or is this all the mad ramblings of one non-physicist fangirl? I would love to hear your thoughts!

  • Clint’n Coal Onyenemezu

    From Nigeria…damm you are ????

  • Darren

    I have read a lot of the comments. My question is how does rita know she lost the power? Wouldn’t she have to die to find out that she lost the power. She would have died before she ever met tom cruise.

  • SDLynx

    If Cage is being sent his memories after he dies, wouldn’t he have to be connected to the network at the beginning of the past-present? He isn’t though, because his blood is only exchanged in the future. And also once he died that first time, he wouldn’t ever have the same blood again if only his consciousness is sent back, right?

  • Stephen Jerome Mesa

    Jenn. Your post is awesome. Great explanation. Makes perfect sense. What about Rita’s soldiers? Why do they not fight? Why when they know where the Omega is do they bother with the beach at all?

  • Brian Su

    Here’s what I think. And I’m gonna work off what you put here, and I respecfully disagree with other bits of your explanation.
    The “send info back” thing is a fairly popular theory, but at the end, he doesn’t absorb the Alpha’s blood. He absorbs the remnants of the Omega. But what we see here is in it’s death is a last ditch effort to survive. An automatic response. However, it’s sending back a blank. The explosion doesn’t ripple back. That’d violate physics more than the Omega existing in non-linear time, and we don’t know time well enough. They don’t refer to the Omega’s death as an explosion but a strange spike of energy. A self-defense mechanism from the death throes. And so it’s essentially rendering itself brain dead.
    But then what about Cage? What are the mimics even after? It’s not a perfectly evolved organism. It’s fought a war for five years, and it technically shouldn’t be able to lose, so having only conquered Europe (aside from the obvious WW2 parallels), it’s pretty friggin’ slow.
    And what are the odds that Cage could meet Rita, who also had gained the ability, when for five years humanity has been throwing everything at it, and for five years millions are dying on each side, and only two people have killed an Alpha so as to absorb its blood. And how does the Omega know to hide out in Lourve? If you think about it, it’s pretty smart, IF the Omega knew that the Lourve was important to humans and would thus likely not be attacked and therefore was a good hiding spot? And how did it know about those locations in Germany?
    Simple. Cage becomes the Mimics. It’s a stable time loop. The Mimics are Cage after becoming immortal through the Omega’s power in existing outside of linear time. He’s already tired of seeing Rita die in that one day, but then what happens after the war? Presumably she believes him because she went through the time loop, but why then was she the only other one with the ability and then was able to train Cage? Cause he remembered. He knew he had to give Rita the ability and then himself the same ability in order to ensure continuity. And it would explain how the Omega knows about Earth’s iconography and why its there. It’s fighting to lose. Because after living so long and becoming a gestalt organism, he wants to die, and so he kills himself. Like Looper. Oh wait….

  • Blake Brandley

    If you watch the movie, it appears that we can physically see the exact moment a mimic dies by the dying of the bioluminescent light they produce. Soldier mimics have an orange/yellow glow, Alpha mimics have a blue glow. Whenever a soldier dies it’s light turns off. I assume that’s how we know it’s dead.

    When Cage destroys the Omega, we can see the Alpha behind him twitch, and then it’s light turns off and it stops moving. Looks like Alphas cannot survive without an Omega.

    This is why I still haven’t found a theory that makes sense to me. If the Omega has the ability to reset time when it personally dies, then it should have reset time the instant it died with the grenade explosion. It didn’t, so then we assume that the Omega lacks that ability. But then Cage absorbs the Omegas blood, and HE resets time. With an ability the Omega didn’t have. By absorbing blood that didn’t contain the ability. WTF.

  • Carlos Morgado

    Plot hole, why once the omega is aware cage has lost his ability to reset the day, doesn’t the omega reset the day? This would delete cages memory of the day (therefore the location of the omega) since he no longer shares the link with the omega and hence would not retain the days memories. What a gap

  • Uglee Sweater

    The Omega could only re-trigger the day through Cruise triggering the reset. Once he did the transfusion the Omega lost it’s ability to communicate with Cruise’s actions. The goal was for Cruise to die after the transfusion on that day and never be able to reset again, but Cruise survived from that point on. The Omega could not retrigger the day because Cruise triggered the reset and never actually died to trigger the reset. There is no hole in the plot.

  • Ash Green

    She had a blood transfusion just like him. She explained that at one point and said her power was gone, she could feel it. When she finds Cage there after the transfusion he tells her its gone too so she does not kill him to reset. She was lucky enough to live this long after she had her transfusion.

  • Ash Green

    I believe he can loop to a different extent and be can take on the rest if the aliens in other parts of the world. He merged with the omega in the end not the alpha. If he couldn’t of looped he would of died and the world would have just mysteriously won London back but he has power to look this he survived, I think this was to set up a happy ending and possible sequel

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  • Radium

    Everything makes sense to me except the concept of actually Reseting the day. What happends to everyone else ? Do they just dissappear and continue their existance in the past but without being aware of the experience they had in the future? So basically anyone of us could have been through this without being able to remember it. Is this more plausible than “classic” time travelling? I mean the whole Universe changes for one single being.

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