Supergirl season 4 episode 15 live stream: Watch online

After so much anticipation, Lex Luthor makes his first appearance on Supergirl this week. Here is how you can watch the episode online.

Well, that could have been worse. Chaos threatened to erupt on Supergirl last week as anti-alien crusader Ben Lockwood staged a rally, inviting both a pro-alien counter-protest and an attack by the Elite. Fortunately, our heroes managed to thwart Manchester Black before too much damage was done, and the whole incident ended up being kind of… inspirational?

To be sure, having individuals on opposing sides of an issue suddenly helping each other is a tad sentimental, given how nuanced the rest of this season has been. But the moment was undeniably moving, captured in a striking shot by James Olsen, who had donned his photographer hat for the first time in a while.

Speaking of James, the ending of the episode obliterated any illusion of all being well. While we assume the CatCo editor will survive, there’s plenty else to worry about.

Below, you can read the official synopsis for this week’s episode, titled “O Brother, Where Art Thou?”, courtesy of The CW:

"JON CRYER GUEST STARS AS ICONIC DC COMICS’ VILLAIN LEX LUTHOR —Secretly furloughed from prison due to failing health, Lex Luthor (guest star Jon Cryer) visits his sister, Lena (Katie McGrath), to seek her help finding a cure. Savvy as ever, Lena is suspicious of Lex’s motives but when she’s faced with a life and death situation, she must decide how she truly feels about her brother. Meanwhile, Supergirl (Melissa Benoist) and J’onn (David Harewood) face off against Manchester Black (guest star David Ajala). James’ sister Kelly (guest star Azie Tesfai) comes to town."

It was bound to happen eventually. Ever since Supergirl introduced Lena Luthor, we have been waiting for her super-villain brother to show up. Lena is a compelling character in her own right, but like Clark Kent/Superman, Lex seemed too integral to the show’s universe to be ignored forever. (By the same token, if The CW’s upcoming Batwoman pilot goes to series, one imagines that Batman will come on board at some point.)

We’re curious how Lex will figure into the season, which is juggling quite a few plotlines as it is already. Will Lena continue her slide toward the dark side? Or will Lex’s appearance remind her why she has spent her career trying to distance herself from her family?

Tawnia Mckiernan directs from a script by Derek Simon and Nikki Holcomb.

"Date: Sunday, March 17Start time: 8 p.m. ESTEpisode: “O Brother, Where Art Thou?”TV Channel: The CWLive Stream: Watch live on Fubo TV. Sign up now for a free seven-day trial. You can also watch on The CW website or app."

Supergirl airs as part of The CW’s Sunday night line-up.