'The Flash' Connects Two Season-Long Mysteries With Surprise Cameo

Tonight's episode of The Flash saw the rise of a new hero as Ralph Dibny stepped up to the plate, but it also saw a surprising person show up, one could well be proof that it is, in fact, all connected.

Spoilers for tonight's episode of The Flash, "The Elongated Knight Rises", below.

In the last moments of tonight's episode, Ralph Dibny/Elongated Man (Hartley Sawyer) stepped up as a real hero to save Cisco/Vibe (Carlos Valdes) and Caitlin/Killer Frost (Danielle Panabaker) from Trickster, Jr. and Prank. With the murderous villains back behind bars where they belong and Ralph fully a member of Team Flash, Ralph and Cisco hit Jitters for some well-earned coffee. Of course, Ralph might finally be the hero Barry (Grant Gustin) believed he could be, but he's still content to let others pick up the tab. When the check comes, Ralph has no money. Cisco isn't going to pay either, and the two squabble. Barry, you see, always pays for Ralph's coffee.

But while the two are fussing over who pays for the lattes, a girl comes up behind them, and slaps down some money for the drinks in a gesture of kindness. The girl? Well for those who were paying attention during the Supergirl hour of the "Crisis on Earth-X" crossover, that girl is very familiar. It's the mystery girl from the West-Allen wedding! She eagerly pays for their coffee and nervously chats with them about it, very much in the same adorkable way she chatted up Barry at the wedding.

While the mystery girl's (played by Smallville alum Jessica Parker Kennedy) reappearance -- and specifically that she did something kind for members of Team Flash -- connects back to one mystery from the first half of the season, it's what we see next that really piques interest. As Cisco and Ralph leave with their coffee, the Mystery Girl sits happily at a table and starts writing in a notebook. As the camera closes in we see very clearly that what she's writing? It's not English; it's the exact same set of symbols that Barry was scrawling on every surface during the season premiere.

Now, what the girl's reappearance and the symbols she's writing mean -- other than possibly "this house is bitchin'" -- remain a mystery, it's clear that her appearance at the wedding really was significant. We have speculated that she might be a descendant of Barry's, either daughter Dawn or granddaughter Jenni, and there are some who think that the symbols that she and Barry have been seen writing (which also appeared on the Thinker's face) could be a form of Interlac, giving some credence to the idea that whoever this girl is she's from the future. And if she is from the future, could she potentially be in Central City to assist Team Flash in stopping The Thinker and saving Barry?

Only time will tell, but one thing's for certain: two of this season's big questions just got connected in a big way.

The Flash airs Tuesdays at 8/7c on The CW.