Fight or Flight (Supergirl)

"Fight or Flight" is the third episode in the first season of the CBS television series Supergirl, which aired on November 9, 2015. It was written by Michael Grassi and Rachel Shuker, and directed by Dermott Downs.

The episode centers on Kara taking on Reactron, who has come to National City to seek revenge on Superman by killing Supergirl, while at the same time take on Cat's plans to do an exposé on Supergirl.

Plot
Cat interviews Supergirl, asking uncompromising questions about the timing of her appearance and her relationship to Superman, causing Kara to accidentally reveal he is her cousin; this fact makes the news the next day. Cat writes an exposé on Supergirl, painting her as having all the stereotypical negative traits of a millennial, which Alex and Hank are not pleased about.

Supergirl is attacked by Reactron, a disfigured man in nuclear-powered armor. Kara manages to damage his armor but he escapes. The DEO refuse to act against him because he is not an alien threat. Winn and James build a high-tech lab in a disused CatCo. office to use as a base of operations. At Lord Technologies, Reactron storms in looking for someone who can repair his suit. Maxwell offers himself in place of another scientist, and Reactron takes him hostage. Kara and the DEO discover Reactron is Ben Krull, who worked in a nuclear reactor where Superman prevented a meltdown, managing to save everyone except Krull’s wife. Blaming Superman for her death, Krull created the Reactron armor to seek revenge, targeting Supergirl to hurt Superman.

Kara goes to Reactron's hideout, where Reactron overpowers her before she is saved by Superman. When she recovers, Kara is angry that James called in Clark to help her, and asks him to leave. At the launch party for the Supergirl issue of CatCo magazine, Kara shares a dance with James and they begin to reconcile, but Reactron breaks in searching for Supergirl. Kara saves Maxwell and Winn, while James distracts Reactron. She learns Reactron is powerless without his power core, which needs to be encased in lead to prevent a meltdown. Kara saves James, then melts a lead statue and coats her hand to extract the core.

At CatCo, Kara overhears James’ conversation with his ex-fiancé Lucy Lane, and believes Lucy wants to resume their relationship. Kara receives an apology text from Clark, and Alex reads the article on Supergirl, telling Kara that Cat was impressed.

Ratings
The episode attracted 1,045,000 viewers for its British premiere, making it the 2nd most watched programme on Sky One for the week.

Critical response
Jeff Jensen of Entertainment Weekly notes in his assessment of the review, "Every week, Supergirl seems intent on addressing its critics and naysayers. This scene here is its explanation for why Superman isn’t a stronger presence on the show. Supergirl, like Kara, is intent on proving that it can stand on its own and doesn’t need Superman to make people interested in it."

Cliff Wheatley of IGN gave the episode a 7.2, saying, Supergirl's third episode leaves the Kryptonian villains behind and instead focuses on Supergirl's desire to prove herself. It's a good episode that takes a few too many missteps with James and gives a lot of screen time to an unlikable Maxwell Lord, but it also goes to great lengths to endear us to Winn – a character that's been underserved thus far – and give Supergirl some real solid internal drama to wrestle with.

Caroline Siede of The A.V. Club gave the episode a positive review, giving it a B+. In her assessment of the episode: "To put it frankly, I don’t think Supergirl needed to address Superman as directly as it does tonight. The showrunners clearly think the Man Of Steel looms large over viewers’ expectations of the series, but I’m not actually sure that's the case. Had the show simply mentioned Superman in the pilot and then moved on I don’t think viewers would have been particularly upset (outside of the usual “Why isn’t the hero from one city helping the hero in another?” complaints that get lodged against every connected universe). But Supergirl clearly wants to clear the air when it comes to Superman, and all things considered I think they do that fairly well. If the concept of bringing Superman into this universe is a little shaky, at least the execution mostly works. "

Stacy Glanzman of TV Fanatic gave the episode a 4.5 out of 5 stars.