Amunet and The Thinker return to wreak havoc in the trailer and synopsis for The Flash midseason finale, 'Don't Run'. Team Flash has had a lot on their plate lately, thanks to big bad The Thinker and his crop of metas. Though last week saw Barry learn the identity of the villain who has been orchestrating events all season long, things are only going to get more difficult for the Scarlet Speedster as The Flash heads towards its winter break.

This week's Crisis on Earth-X crossover saw Barry and Iris finally get married, despite the best efforts of Nazis from the eponymous Earth-X. Now that things have returned to normal, Central City's rogues are coming back in force. Along with The Thinker and his partner The Mechanic, Team Flash still has half a dozen new metas to contend with. Then, there's the villainous Amunet, who's not ready to let Caitlin off the hook. Meanwhile, with Iris calling the shots at S.T.A.R. Labs, the happy couple doesn't seem to have time for a honeymoon right now.

The CW has now released the trailer and synopsis for The Flash midseason finale, 'Don't Run', which will arrive next Tuesday. Based on the trailer, it seems that The Thinker is already ramping up his evil plan, as he threatens Joe and manages to trap Barry. Meanwhile, the synopsis for the episode reveals what will happen when Amunet (Katie Sackhoff) returns to the show:

KATEE SACKHOFF RETURNS AS AMUNET — Amunet (guest star Katie Sackhoff) kidnaps Caitlin (Danielle Panabaker) and puts meta-dampener handcuffs on her to keep her from turning into Killer Frost. Amunet tells Caitlin she needs her to perform a tricky medical task and if Caitlin fails, Amunet will kill her. Meanwhile, The Thinker (guest star Neil Sandilands) traps The Flash (Grant Gustin) in a speedster-proof prison. With the clock ticking, The Team doesn’t have the time or resources to track both Caitlin and Barry so Iris (Candice Patton) is forced to choose who to save. Stefan Pleszczynski directed the episode written by Sam Chalsen & Judalina Neira

Caitlin hasn't had a lot to do over the past few seasons of The Flash, but her evolution as Killer Frost has finally given the actor behind her, Danielle Panabaker, more to work with in season 4. By giving her a nemesis of her own, Barry won't be the only one trying to juggle two lives and protect themselves from vindictive rogues in 'Don't Run'.

Similarly, The Flash season 4 has finally given Iris more agency, now that she's taking point for Team Flash's various missions. She's already been shown using her journalistic skills to delegate the team's resources and execute plans, but it looks as if the upcoming episode will provide Iris with her first big test as the leader of the group. While Caitlin is unlikely to die if Iris chooses to save her new husband, Killer Frost could come back under the sway of crime lord Amunet.

MORE: Did Crisis On Earth-X Introduce Barry & Iris' [Spoiler]?

The Flash midseason finale, 'Don't Run', airs next Tuesday, December 5 at 8pm EST on The CW.

Source: The CW