The Flash
Barry (Grant Gustin) learns an enemy has returned in episode 11 of "The Flash" Season 2. The CW

The Turtle (Aaron Douglas) may turn out to hold the answer to stopping Zoom (Tony Todd) on "The Flash" — even if Dr. Wells (Tom Cavanaugh) may have killed the criminal in cold blood to get it. However, before Barry (Grant Gustin) can handle Season 2 's supervillain speedster, he will first have to face the one he thought was already gone in episode 11, "Reverse Flash Returns."

If the episode title did not already give it away, according to the CW's synopsis for episode 11, Eobard Thawne, aka Reverse Flash (Matt Letscher), is back in Central City. Before fans get any ideas, no, this has nothing to do with Dr. Wells from Earth 1. In fact, the Thawne Barry will face in episode 11 is the villain before he ever lost his speed and needed to hijack Wells' body.

The synopsis reveals that Barry suspects the villain has returned after Cisco (Carlos Valdes) gets a vibe of Thawne. Their suspicions are confirmed when Thawne soon after attacks Mercury Labs.

So, what is Thawne, who is supposed to be erased from existence after Eddie's (Rick Cosnett) suicide sacrifice in Season 1, doing back? The promo may have the answer. In the teaser video, Earth 2 Wells has an explanation for the strange reappearance and it has to do with time travel.

"This is how he learns about you, all of you" Wells tells the team at STAR Labs, referencing a sort-of time loop with the events in Season 1. "This is his origin story and there is nothing you can do about it."

Watch the promo for "Reverse Flash Returns" below:

Will Barry be able to stop the Reverse Flash ... again? Fans will have to wait to find out. "The Flash" airs Tuesdays at 8 p.m. EST on the CW.