The Rest of 'Supergirl' Season 4 Will Explore Lex Luthor and James Olsen's Relationship

Like many fans, Lex Luthor (Jon Cryer) still thinks of Supergirl's James Olsen as "Jimmy," something played for laughs a few times during tonight's episode, titled "O Brother, Where Art Thou?" That, of course, is because James was Superman's pal during the time when Lex was trying to kill the Man of Steel -- and that baggage is going to come into play during the rest of the season, now that both James and Lex have taken Lena's cure. In fact, the baggage they have together will drive a lot of their shared storyline for the rest of season four.

On tonight's episode, the pair are both in different kinds of mortal danger; Lex has suffered a stroke relating to his cancer, which was apparently brought Kryptonite poisoning in a misguided effort to kill Superman years ago. Furloughed from prison due to his illness (it's nice to be a billionaire, we guess), Luthor seeks out help from Lena, his sister who he knows can perfect her miracle cure, especially if he is there to help her out with it. James, meanwhile, is suffering from a gunshot wound he suffered at the end of last week's episode, which has him bleeding out in the hospital and in a more imminent kind of mortal danger.

"I think that the impact of Lex Luthor on James' character is profound moving forward," said executive producer Robert Rovner during a recent screening of tonight's episode. "And it's something he deals with the rest of the season and will kind of see them lock horns by the season finale." His co-showrunner Jessica Queller added, "And we'll excavate their history a little bit more."

That starts next week, with a Lex-centric episode. You can check out the official synopsis for that one below.

"The House of L" — (8:00-9:00 p.m. ET) (TV-PG, V) (HDTV)

LEX LUTHOR CONTINUES TO WREAK HAVOC — In the wake of Lex Luthor's (guest star Jon Cryer) return, the show flashes back to what he's been doing for the last two years and how his secret machinations and plans have affected Supergirl (Melissa Benoist) and Lena (Katie McGrath).

Carl Seaton directed the episode written by Dana Horgan & Eric Carrasco.

Supergirl airs on Sunday nights at 8 p.m. ET/PT, before episodes of Charmed on The CW.

Supergirl airs Sundays at 8 p.m. ET/PT, before episodes of Charmed on The CW.