Since losing her alter ego, Caitlin Snow (Danielle Panabaker) hasn’t been the same. But in the newest episode of The Flash, Caitlin learns that Killer Frost was with her a lot, lot longer than she realized — even before the particle accelerator exploded that ushered in an era of meta-humans in Central City.

In “Think Fast,” Devoe (Neil Sandilands) moves forward with his grand plan to bring about the Enlightenment, which would make everyone geniuses but lose any and all memories and emotions — love, hate, all of it. Ultimately, though Team Flash succeeds in destroying one of Devoe’s satellites, it wasn’t enough to stop Devoe entirely, leading to chaos that kicks off the season finale next week.

But in a separate subplot, Caitlin has been trying to “find” Killer Frost, her meta-human alter ego that has disappeared since fighting Devoe head-on weeks ago. While training with Barry (Grant Gustin) and Cisco (Carlos Valdes), Caitlin unlocks a repressed memory of her childhood: The very first time she became Killer Frost. But how? This was years before the particle accelerator explosion. It would be like a planet existing before the Big Bang. In this case, Killer Frost awoke in Caitlin long before anyone else was a meta-human.

It’s unlikely that this is time-travel shenanigans. The adventures of the Legends on Legends of Tomorrow are on pause, and the cliffhanger ending with John Constantine looks like the show is going towards a darker, supernatural territory than the usual science-fiction.

The comics are no help here, either. When it comes to DC Comics, Caitlin Snow is a relatively recent addition, making her debut in the New 52 continuity in 2013. In her new origins, Caitlin Snow was a scientist in the Arctic, and she became Killer Frost when H.I.V.E. infiltrated the facility and nearly killed her when she was inside a thermodynamic engine. There’s nothing about a traumatic childhood.

Devoe The Flash
Meanwhile, Devoe is one step closer to his master plan.

The Flash is wandering into unknown territory with this Killer Frost/Caitlin Snow reveal, and it’s one of the first engaging mysteries in a long time. It’s just too bad the season finale is next week.

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

Photos via The Cw, The CW