The heroes on Legends of Tomorrow have had their hands full this season chasing down the anachronisms they created when they broke time saving the world from the Legion of Doom at the end of the show's second season. From chasing down time-displaced figures such as Julius Caesar and Helen of Troy, to going back in time to stop the Vikings from worshipping a blue stuffed animal named Beebo and thus conquering the world, the Legends have gone on adventures that have put them on the wrong side of authority that might even be evidence that the timeline is imploding around them.
But it's not just the adventures the Legends have been on this season that could be a sign that something is a little off with the timeline. A particular moment during the episode "Phone Home" may have called into question one of the biggest events in Arrowverse history: last season's "Invasion!" crossover.
As fans may recall, last season's crossover event wasn't quite the movie-like epic that was this year's "Crisis on Earth-X", but it featured a foe every bit as dangerous in the alien race known as Dominators. In "Invasion!", a meteor crashes outside of Central City and turns out to be a spaceship filled with Dominators, a technologically advanced alien race with immense mental abilities, including mind control and telepathy. They kidnap the President of the United States, and it comes to light that this isn't the first time the Dominators have visited Earth. Turns out that the aliens had visited in 1951 where they made a treaty with the United States government to limit metahuman activity. The Dominators returned to Earth decades later in response to The Flash's manipulation of the timeline. If the Flash doesn't turn himself over, the Dominators plan to deploy an anti-metahuman bomb which would kill all the metahumans on Earth.
The assembled heroes are ultimately successful in stopping the Dominators -- Firestorm manages to transmute the bomb into a harmless liquid and save metahuman kind while the aliens retreat thanks to the use of a pain-inflicting nano-weapon -- but one of the lasting consequences is that it's established that aliens exist in the Arrowverse, and not just on Supergirl's Earth-38.
Going back to this season, specifically the fourth episode "Phone Home". When it's discovered that young Ray has befriended a baby Dominator, the Legends team knows from experience that Dominators aren't a race they want to mess with, but new team member, Zari (Tala Ashe) is genuinely surprised to find out that aliens exist, commenting "so aliens are real." With Zari being from the future (2042 specifically) it seems like an odd statement to make. If Zari, who is from the not-so-distant future, isn't aware that aliens are real, does that mean "Invasion!" never happened?
The knee-jerk reaction is to say that yes, the events of "Invasion!" may have changed thanks to the timeline issues we've seen this season on Legends. However, the other Arrowverse heroes who aren't privy to the anachronism situation seem to have recollection of the events -- Dominators are specifically referenced by Supergirl (Melissa Benoist) during "Crisis on Earth-X". If that's the case, why doesn't Zari know about aliens?
The likely answer is that the future of the Arrowverse is far bleaker than we've seen. When the team finds Zari in 2042, they also find out that the world is not as they'd expect it. Seattle is under martial law by A.R.G.U.S. and the group, that has long been friendly towards the heroes thanks to its association with Team Arrow, is now actively hunting down metahumans. There's even a law in place making it a crime to be one. With A.R.G.U.S. now being an antagonistic force instead of an ally, it's entirely possible that as part of their control over the country that they've used propaganda to erase the existence of aliens as well as the metahuman heroes who saved the world from them.
It's a scenario that paints a very 1984-like picture of the future of the Arrowverse, but it's also a move that might already be in motion. The heroes themselves appear to have largely erased the Nazi invasion of "Crisis on Earth-X" from the public's memories, while on Arrow Star City passed "anti-vigilante legislation" that could be a precursor to the Anti-Metahuman Act of Zari's future, a possibility even more sobering when you remember that we've seen a possible Star City from just four years past Zari's time, and it's not a fun place.
Legends of Tomorrow is presently on winter hiatus and will return to The CW in February.