Actress Jessica Parker Kennedy plays the Mystery Girl in Season 4 of 'The Flash'

After what felt like a far too-long hiatus, the enigmatic Mystery Girl finally reappeared on The Flash, dropping a huge bombshell along the way: The Mystery Girl is a confirmed speedster.

Further spoilers follow for The Flash Season 4, Episode 20: “Therefore She Is”

Tuesday’s episode “Therefore She Is” focuses mostly on the DeVoes, specifically Marlize and growing doubts about The Thinker’s mysterious plans for the so-called “Enlightenment.” We even get flashbacks to their first meeting and courtship, which reveals that Clifford despises technology and how consumed with it mankind has become (ironic considering how much futuristic tech he uses). He begins stealing high-end machine parts to craft a collection of satellites that will generate enough dark matter to effectively lobotomize all of humanity and reboot them into a “simplified state” with no intellectual capacity.

But a far more interesting development happens when, during a baby shower for Cecille, we were all treated to the following surprise delivery when the Mystery Girl brought a present and her typical mysterious yet strangely cheery self:

“Looks like you’re due 21 nights from today!” the Mystery Girl says, handing over a diaper bag. “It looks like it’s a gift from someone who wanted you both to know how special you are, someone who understands that time is precious and right now is all we’ve got.” (This is exactly the kind eerily prescient language she’s used since she first met Barry at his wedding.) As soon as Iris walks towards the door, the Girl’s expression changes, and when Joe turns to ask her a question. She’s gone.

It may have felt like a tease for her to disappear so quickly, which merely hints that she could be a speedster. But a moment later, The Flash proves beyond a measure of a doubt that this Mystery Girl is indeed a speedster:

This would explain why she knows how to write that weird Speed Force language. She’s not just a speedster because she also has enough experience with the Speed Force itself to know the language better than even Barry does.

Note that while she hides around the corner, she has a decidedly more grim expression on her face, one similar to the one we saw in her last appearance at the end of “Enter Flashtime.”

You’ll probably also notice that her lightning is a mixture of yellow and purple, which is the exact mixture of Barry and Iris’s speedster lightning colors. Considering a popular theory posits that the Mystery Girl is actually their daughter from the future, Dawn Allen, then fans are probably freaking out right about now.

There’s been confirmation already that we’ll eventually learn her true identity, probably as part of the season finale on May 22 that will set up Season 5. So for now, we’ll have to sit tight with our fan theories — like my theory that she’s actually a genderbent Bart Allen — until we know for sure.


The Flash airs Tuesdays on The CW at 8 p.m. Eastern.

Photos via The CW