Supergirl sure knows how to stretch out a two-part episode. After last weekend's "Back From the Future - Part One," which brought back Winn Schott (Jeremy Jordan) and revealed some post-"Crisis on Infinite Earths" hard truths about Brainiac-5, the series will leave fans guessing for two weeks before returning on February 16 with "Back From the Future - Part Two," which will wrap up those threads and chart the new status quo for the post-Crisis world on Supergirl. The CW has just released the official synopsis, which does not tell fans very much about how anything will wrap up, but teases that Winn will have to "face his greatest fear" along the way.

The series is one of the shows most directly impacted by the post-"Crisis" world, since Lex Luthor has set himself up as a hero to the world in this new reality, where Earth-38 has been merged with Earth-1 and so a lot of history is kind of up in the air. And Supergirl, Martian Manhunter, and Alex Danvers have made it their mission to keep an eye on Luthor.

"I think it's important for us to keep him in check. At the same time, we don't necessarily just want to stop him; first of all, we have to find out what he's doing," explained David Harewood, who plays J'Onn J'onzz, and who directed the first half of the "Back From the Future" two-parter. "Winn comes back with the knowledge that Lex is a hero. So I have to kind of fill him in as well about exactly who Lex Luthor is, and some of it's quite funny. It's great for J'onn to pick up where they left off, because, as you say, that was also a chance to J'onn to find some life in the ... when he worked with Winn in the DEO, he was able to sort of play a little bit more of the comedy. It's great to pick up on that again."

You can check out the official synopsis below.

BRAINY MUST CHOOSE BETWEEN ALEX AND LEX; JEREMY JORDAN GUEST STARS – Supergirl (Melissa Benoist) helps Winn (guest star Jeremy Jordan) face his greatest fear. After Alex (Chyler Leigh) sets out to find evidence against Lex (guest star Jon Cryer), Brainy (Jesse Rath) must decide between helping his friend or continuing to secretly work for Lex. Alexis Ostrander directed the episode written by Rob Wright & J. Holtham.

Supergirl airs on The CW at 9 p.m. ET/PT on Sundays, following episodes of Batwoman. "Back From the Future - Part Two" will debut on February 16.