Roulette and Miss Martian Come to Supergirl in "Survivors" Synopsis

Roulette comes to National City, bringing her superhuman fight club with her, while J'Onn J'Onzz struggles to get to know Miss Martian, in the official synopsis for "Survivors," the fourth episode of Supergirl's second season.

The CW released the official synopsis tonight, giving fans an idea of what to expect when Aquamarine's Dichen Lachman and Dreamgirls's Shannon Leal come to the series.

HANK AND M'GANN GET TO KNOW EACH OTHER; AN ALIEN FIGHT CLUB RUN BY ROULETTE GRABS SUPERGIRL'S ATTENTION — When Kara (Melissa Benoist) and Alex (Chyler Leigh) investigate the murder of an unregistered alien, the trail leads to an alien fight club run by Roulette (guest star Dichen Lachman), the ringmaster who commands aliens to fight in mortal combat for the entertainment of rich humans.

While trying to stop the fighting, Supergirl and Martian Manhunter find themselves up against a surprising opponent. Meanwhile, Hank (David Harewood) is thrilled to have found another Martian and tries to get to know M'Gann (guest star Sharon Leal) better. Supergirl takes Mon-El (Chris Wood) under her wing and begins to train him.

James Marshall directed the episode, written by Paula Yoo & Eric Carrasco.

Supergirl airs Monday nights at 8 p.m. ET/PT on The CW. "Survivors" will debut on October 31, 2016.