Could the circumstances of Barry Allen's disappearance on The Flash have been altered by his daughter's travels to the past, causing him to vanish earlier than anticipated? There is evidence that this might be the case. It cannot be denied that Nora West-Allen's trip to 2018 has already changed the past (and the future), and those changes can only become more significant the longer she remains in a time that is not her own, perhaps eventually altering her father's destiny.

The Flash season 5 has largely focused on Nora West-Allen, who was formally introduced into the series in the season 4 finale. The "supposed" daughter of Barry Allen and Iris West from the not-too-distant future of 2049, Nora adopted the superheroic identity of XS and followed in her father's footsteps as a CSI and a superhero. It was quickly revealed, however, that Nora's trip to the past was far from the accident she originally claimed was responsible for her travelling to 2018. She finally confessed that she had gone back in time intentionally to get to know the father she only knew from family legends and museum exhibits (including the Arrowverse's future Flash Museum), as Barry Allen disappeared in 2024.

Related: Arrowverse's THREE Alternate Futures: 2038, 2042 & 2049 Explained

While the early episodes of The Flash season 5 confirmed that Barry's destiny was still on track, the recent Arrowverse crossover event Elseworlds suggested that the crisis which causes The Flash to disappear has been bumped up five years. While there are several things that might have caused this occur, Nora is the prime suspect as the only rogue time-traveler seen to have been operating within the relevant time period.

The Flash's Barry Allen Disappears In 2024

Future Flash Missing 25 Years Season 5 Newspaper

Barry's destined disappearance in 2024 has been a matter of record since The Flash season 1. It was here that Reverse-Flash, in the guise of Harrison Wells, first looked at a newspaper from April 2024, which had the headline "Flash Missing, Vanishes In Crisis." Later in the season, Barry Allen would discover this article and learn that his future self disappeared while fighting alongside Green Arrow, The Atom, and Hawkgirl. The same newspaper also made mention of the skies turning red -  an meteorological event of great significance to those comic readers familiar with Crisis on Infinite Earths. This was the same event where Barry Allen vanished while trying to save the multiverse and was presumed dead.

The premiere episode of The Flash's season 5 confirmed that Barry Allen's destiny was still on track. Nora West-Allen showed her father a second newspaper from her time dated April 2049. This newspaper headline spoke about how it had been exactly 25 years since Flash disappeared during some manner of crisis. The ultimate end for Barry Allen was exactly the same, though the article now made mention of superheroes like Supergirl and Batwoman showing up to join the battle, as well as Reverse-Flash being seen leading an army of shadow demons. This last bit was another nod to Crisis on Infinite Earths.

Nora West-Allen Screwed Up Flash's Timeline

Nora West-Allen The Flash 100th episode

As The Flash season 5 progressed, it became clear that Nora West-Allen's presence was altering the events of her past. In The Flash season 5 premiere, Nora's efforts to impress her father resulted in a metahuman criminal called Gridlock evading capture. This surprised Nora, as she said that the records of her time showed Flash easily defeating Gridlock and only fighting him once. Another major change came at the end of the episode, when Gridlock became the first victim of the serial killer named Cicada. Nora later said that, in her time, the first victim of Cicada was a man named Floyd Belkin.

The centerpiece of the Flash's other major subplot in season 5, the murderous Cicada was a metahuman who had the ability to neutralize the super powers of other metahumans. According to Nora, Cicada was destined to become the one villain that Flash was never able to stop. Even the assistance of Green Arrow, the Legends, and Supergirl wasn't enough to enable Team Flash to discover Cicada's true identity, much less put a stop to his killing spree.

Related: The Flash Fixes Plot Hole By Secretly Changing Arrowverse History

At Nora's prompting, Team Flash enlisted the aid of Harrison Sherloque Wells (the greatest detective in the multiverse) in order to determine Cicada's identity. It was quickly revealed that while Sherloque was a brilliant detective he was also lazy and he had jumped to conclusions regarding Cicada's identity on Earth 1. Sherloque had once determined that the Cicada of one Earth was a man named David Hersch and, having been tasked with tracking down Cicada on 36 other Earths, always accused that Earth's version of David Hersch. It was then that Team Flash realized that Nora's interference in the destruction of STAR Labs satellite had changed the trajectory of the shrapnel that should have empowered David Hersch, resulting in someone else becoming the Cicada of Earth 1.

Thanks to Nora's suggestion that they recruit a different version of Harrison Wells to find Cicada (something the Team Flash of her timeline apparently never tried), the team was eventually able to identify Cicada as a man named Orlin Dwyer. They also discovered, thanks to Nora's suggestion in The Flash season 5 midseason finale, that they create a piece of meta-tech that could negate Cicada's powers, that his abilities to negate metahuman powers didn't work on metahumans like Killer Frost who gained their powers through medical experimentation. This gave Team Flash two valuable weapons they didn't have before and further altered Nora's future, where Cicada's identity was supposed to have remained a mystery. At this point, it's almost impossible to guess just how badly Nora's actions may have changed her past and the timeline as a whole.

Page 2 of 2: Barry Disappears In 2019 & Flash's Future

Barry Allen Time Travels in The Flash

Barry Disappears In A Crisis... In 2019

Barry's fate was altered again in the Arrowverse crossover event Elseworlds. The three-episode crossover saw a sinister doctor named John Deegan entrusted with the Book of Destiny - an artifact that had the power to rewrite reality. Joining forces with Supergirl, Superman, and Green Arrow, Barry Allen eventually hit upon a plan to strike at Deegan, who had given himself the powers of Superman in the new reality. The plan required that he and Supergirl travel around the earth in opposite directions, eventually moving fast enough and building up enough weight and velocity that their combined power would slow down time on a relative level and give Superman the opening he needed to recover the Book of Destiny.

The problem with this plan was that Superman foresaw, during a brief glimpse at the Book of Destiny earlier, that it would end in Flash and Supergirl dying. This prompted Green Arrow to seek out The Monitor - a cosmic being who gave Dr. Deegan the Book of Destiny as part of a test of Earth-1's heroes. Green Arrow confronted the Monitor over how pointless his test was, if his stated goal was to find heroes powerful enough to save all of reality from a coming crisis. While granting that Green Arrow had a point, the Monitor said that a price would have to be paid to maintain the balance and change the destinies of Flash and Supergirl.

Related: Crisis On Infinite Earths Should Kill Superman, Not Supergirl

It's unknown what price Green Arrow agreed to pay, but Supergirl and the Flash did survive the events of Elseworlds. Yet the event ended on an ominous note, with a masked inmate in Arkham Asylum assuring the comatose Dr. Deegan that "... everything is as it should be. The stage is set. Worlds will live. Worlds will die. And the universe will never be the same." Even without the character being identified as the Psycho-Pirate and the line being a clear allusion to Crisis on Infinite Earths, the final outcome of Elseworlds was made clear by a title card announcing that Crisis on Infinite Earths will be 2019's Arrowverse crossover.

Precisely why Crisis on Infinite Earths is occurring five years ahead of when it was suggested is unclear, unless audiences consider the midseason finale of The Flash season 5. It was that episode that revealed Nora West-Allen was working for Reverse-Flash, who's imprisoned in Iron Heights Penitentiary in her time. Nora has been apparently been sending Thawne information on the current events in 2018 in a special time language for time travelers.

It's unknown precisely what Reverse-Flash's plans are for this information, but it would certainly be within his means to calculate a way to alter the timeline so that his worst enemy's apparent destruction was pushed forward five years to 2019. In The Flash season 1, a time-displaced Eobard Thawne was able to alter the timeline so that the accident that transformed Barry Allen into the Flash occurred seven years earlier, on December 11, 2013. Before Thawne went back in time and replaced Harrison Wells, Barry Allen didn't become the Flash until sometime in the year 2020 and the time-displaced Reverse-Flash was unwilling to wait that long for his arch-enemy to gain the power that Thawne needed to steal in order to get back to his own time.

What This Means For The Flash's Future

Grant Gustin as Barry Allen in The Flash TV Show Season 5

Virtually anything is possible at this point given Thawne's capacity for planning ahead as well as the advantages he possesses when it comes to future technology and knowledge of Barry's life. The biggest question in all of this is, what's Thawne's ultimate goal? That answer largely depends on when this latest version of Thawne was created. We know the Thawne we see in prison in 2049 has to be some kind of time remnant given that the Reverse-Flash has been erased from reality twice already. This does leave us with one important question: why hasn't the Black Flash arrived to remove this version of Thawne from reality, as it did all of the other time remnants Thawne created in Legends of Tomorrow season 2 finale?

Related: How The Arrowverse Has Already Set Up Crisis On Infinite Earths

Given that this remnant of Thawne is wearing the face of Harrison Wells, he had to have been created sometime after Thawne adopted Wells' identity in the past. This means that he may share the first season Thawne's goal of returning back to his proper time in the 22nd century. However, if he's aware of his status as a time remnant and is uncertain how much time he has left, it's entirely possible he may have decided to go for broke and work to hasten Barry Allen's destruction out of pure spite. Perhaps by pushing the Crisis destined to end Barry's life forward a few years? As is usually the case with The Flash, the only certainty to the future is that it's uncertain. That's doubly true when the Reverse-Flash is involved. Nora West-Allen helping her father's nemesis adds another wrinkle to the already tortured fabric of space and time and Barry's continued survival until Crisis On Infinite Earths may not be guaranteed.

More: When The Flash Season 5 Returns In 2019 (& What to Expect)