The synopsis for Season 2, episode 4 of “Supergirl” revealed a few new details about Roulette’s (Dichen Lachman) underground alien fight club.

According to synopsis for the episode, titled “Survivors,” Roulette’s illegal alien fight club hosts mortal combats between a pair of aliens for the entertainment of rich humans. Kara (Melissa Benoist) and her adoptive sister Alex (Chyler Leigh) discover the fight club while investigating the murder of an unregistered alien. While trying to stop the operation of the fight club, Supergirl and Martian Manhunter (David Harewood) find themselves up against an unexpected opponent.

Comicbook.com was first to report about Roulette’s underground alien fight club. The website also revealed that Roulette, who runs the business, is eager to get the Girl of Steel in the ring.

News that “Supergirl” is bringing DC Comics character Roulette into the show first surfaced when Lachman was spotted filming a scene on the set of The CW series last Sept. 13. As seen in the photos obtained by YVRShoots, the 34-year-old actress was wearing a long red dress with a side split that shows her leg snake tattoo.

According to YVRShoots, the sequence being filmed that night involved Science Police detective Maggie Sawyer (Floriana Lima) escorting Lachman’s character and meeting up with Alex. The context of the scene is unclear, but it seems that Maggie is turning over Roulette to the DEO where Alex works.

Three days after that filming night, the “Last Ship” actress confirmed her casting in a video clip she uploaded on Instagram.

“I just want to thank everybody for all the excitement about me appearing on ‘Supergirl’ as Roulette,” the Nepali-born Australian actress said. “The cast and crew are working so hard and there are such incredible people. I’m really excited to be on the show, and I can’t wait for you to see it.”

“Supergirl” Season 2, episode 4 airs Monday, Oct. 31, at 8 p.m. on The CW. Next week’s episode, titled “The Last Children of Krypton,” airs on Oct. 17. Check out the synopsis for Season 2, episode 2 below:

“CADMUS attacks National City with a kryptonite powered villain who ends up seriously hurting Supergirl. Superman (Tyler Hoechlin) blames Hank because the kryptonite was stolen from the DEO. Meanwhile, Kara’s first day at her new job doesn’t go as planned after she meets her new boss, Snapper Carr (Ian Gomez).”