When Kara and Alex investigate the murder of an unregistered alien, the trail leads to an alien fight club run by Roulette, 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, J'onn is thrilled to have found another Martian and tries to get to know M'gann better. Supergirl takes Mon-El under her wing and begins to train him.
In Mon-El's flashback, the remains of the destroyed Krypton rain down onto Daxam. During the chaos, Mon-El escorts the prince to a Kryptonian ship. When Mon-El enters the pod to start up the engine, the prince closes the hatch and stays behind leaving Mon-El to escape.
After Mon-El finishes telling the team of his job as the palace guard and his recollection of how he got to Earth, he is confined to the D.E.O. headquarters. J'onn leaves to attend to personal manners.
At CatCo, Kara relays the alien murder story to Snapper. Snapper then peppers her with questions which Kara doesn't have answers to. He tells her it's just a half-baked idea and tells her to go get more on the scoop.
Winn tells Alex about her alien perp, a Brevakk, and prepares to organize a strike team. Alex turns it down and calls Maggie instead. They question the Brevakk, but he fights back. They pin him down to arrest him, but armed men show up, taze them, and kidnap the alien.
At the D.E.O., J'onn prepares to go after the armed men. Alex and Kara notice the extra grumpiness. J'onn tells them of M'gann and how she didn't seem to want to psychically bond with him as Green Martians usually do. They tell J'onn to apologize and let M'gann know how he feels. Kara talks to her A.I. "mother" about her first published article. Mon-El accidentally barges in and asks about the hologram. After Alura starts to talk bad about Daxamites, Kara shuts the program off. She tells him that the hologram helps her feel less alone. Mon-El proposes that Kara could accompany him outside the D.E.O. instead of confinement but Kara refuses and leaves.
Alex meets Maggie at an illegal alien fighting ring attended by National City's elites. A woman introduces the attendees to the fighters, Quill the Brevakk and M'gann M'orzz (aka Miss Martian). The fighters battle, but M'gann uses her Martian powers to subdue Quill. Supergirl arrives and the organizer pits her against Draaga. As the fight turns against Supergirl, Alex and Maggie fire shots into the air to disperse the crowd and rescue Supergirl.
At the D.E.O. infirmary, they tell J'onn of M'gann's participation in the fight club. Meanwhile, Mon-El convinces Winn to take him into the city by letting Winn design him a superhero costume and name.
Kara returns to CatCo and tells Snapper of the murder's connection to an alien fighting ring. Snapper asks about her sources and prompts her to not to come until she brought him a source.
Winn and Mon-El go partying at a bar. After a while, Winn gets wasted. Mon-El accidentally breaks someone's arm in an arm wrestling match so they leave.
J'onn confronts M'gann about her participation in the fights. M'gann defends herself saying she does it for survival, not for the money and that she has never killed anyone in the ring. J'onn retorts by saying that as the last of their kind, they should be preserving the memories of their people but she claims that she would rather forget. As J'onn leaves, she gives him the name of the ringleader, Roulette known by the real name Veronica Sinclair.
Supergirl attacks Sinclair's limo. Sinclair claims that aliens aren't people so they don't have any rights. She believes she is doing them a favor by giving them an opportunity to earn glory and money. Sinclair tells Supergirl that she is naive for thinking that anyone cares what happens to aliens.
The next day, Kara tells them of the encounter with Sinclair and J'onn tells them that he knows of Winn and Mon-El's escapade last night. J'onn also tells them of his encounter with M'gann and stresses that he has worked so hard to make humans trust aliens and that it can take one to undo that work. Kara tells Mon-El about how it will take time from him to adjust to his new powers and living in the world. They talk about their parents and how both of theirs were flawed people. As Kara walks out, Mon-El mentions having seen Draaga before on Warworld and that Draaga had an injury to the right leg.
J'onn apologizes to M'gann outside the Alien Bar. Roulette and her goons arrive on scene, subdue J'onn, and kidnap him. At the D.E.O., they work on finding J'onn. Kara goes to Lena Luthor for help. Lena reveals that she knows Roulette from boarding school and gives Kara the location of the next fight.
At the fight, Roulette introduces the two Martians to the crowd and forces them to fight to the death. They fight and transform into Green Martian forms. M'gann manages to pin J'onn down and tells him she will do anything to survive but J'onn convinces her that she fights because she is guilty for surviving. M'gann tells Roulette that she refuses to kill J'onn. Roulette releases Draaga to fight the Martians. Alex, Maggie, and the police arrive and arrest crowdgoers. Supergirl also arrives and is able to defeat Draaga with a well-placed kick to Draaga's right leg. Supergirl and the police go to arrest Sinslair, but she is surrounded by her alien followers. Sinclair claims that they protect her because she provides for them. Supergirl convinces the other aliens that fighting against each other distracts from fighting against people like Cadmus and Roulette who think aliens are a menace. Roulette turns to escape, but her alien followers turn on her. Maggie arrests her. Later, Maggie is forced to release Roulette due to orders from higher-ups. Alex tells Maggie she is a great cop and asks Maggie for a drink, but Maggie has plans with a date.
Kara shows Snapper her full article, complete with police reports and a first person account from Supergirl.
Later, Kara tells Mon-El that she had the D.E.O. release him into her custody rather than for him to remain confined. Kara agrees to help him train to be a hero to make up for her lost opportunity to raise her cousin.
J'onn meets M'gann at her her apartment. M'gann apologizes for her actions. J'onn tells her that he will always be around if she needs him. After J'onn leaves, M'gann shapeshifts, revealing herself to be a White Martian.
- This is the first episode of the series not to feature Mehcad Brooks (James Olsen).
- This episode pays homage to the Smallville sixth season episode "Combat" Whereas Clark is introduced to an underground revolving fight club, in order to put a stop to an alien from the Phantom Zone of which murders the losers.
- This was Laura Benanti's final appearance as Alura before the role was recast with Erica Durance in "Girl of Steel".
|Supergirl season 2|
|"The Adventures of Supergirl" • "The Last Children of Krypton" • "Welcome to Earth" • "Survivors" • "Crossfire" • "Changing" • "The Darkest Place" • "Medusa" • "Supergirl Lives" • "We Can Be Heroes" • "The Martian Chronicles" • "Luthors" • "Mr. & Mrs. Mxyzptlk" • "Homecoming" • "Exodus" • "Star-Crossed" • "Distant Sun" • "Ace Reporter" • "Alex" • "City of Lost Children" • "Resist" • "Nevertheless, She Persisted"|