CW's newest DC hero series opened with with Mon-El telling the story of how he ended up in a Kryptonian pod. As Krypton was destroyed, his planet Daxam was also dying. He was a palace guard for the royal family, and while attempting to save the prince, the latter tricked him into getting into the Kryptonian ambassador’s leftover pod; programmed it for him to be locked inside and ordered him to save himself. The prince wanted to remain with his people.
He then asked Supergirl, J’onn, Alex, and Winn to go out somewhere to have some fun but Mon-El was not allowed to go out until the DEO learns the full extent of his powers. J’onn suddenly excused himself for something “personal". This surprised Alex and Supergirl. Thereafter, Alex got a call from Maggie about a dead body found in the metro.
Alex and Supergirl meet up with Maggie who has discovered a dead alien. Supergirl confirmed the alien’s specie, and Alex and Maggie ran circles around her in the detective department, looking out for possibilities and clues as if they have been partnered up for years. Alex then found a thorn buried in the alien’s shoulder and took it to get analyzed in the DEO’s lab.
Meanwhile, J’onn went back to the alien bar to see M’gann and asked her about her history, or herstory for gender sensitivity. She then said that she was in the worst internment camp on Mars and endured harsh conditions and threats of random killings every day.
She was saved by a White Martian, which hugely surprised J’onn. However, she said that the White Martian broke ranks and smuggled her off of Mars and she has not looked back. J’onn then asked M’gann if she would like to “take the bond” with him. This freaked her out because J'onn was coming on way strong.
At the DEO, Winn told Alex that the thorn she found is from an alien called a Bravak, and that thanks to the Alien Amnesty Act, one Bravak has been registered in National City. He then gave Alex the location. Alex then called Maggie to go with her searching for the Bravak.
Alex and Maggie then found themselves in an underground fighting club where aliens fight for money. The schedule fight was between the Bravak whom Alex and Maggie were looking for, and M’gann. She was a willing participant in the fight club, undefeated, and goes by the name Miss Martian.
Alex had called Supergirl as backup, and she arrived at the fight club and ended up fighting an alien gladiator named Draaga. Back at the DEO, Alex and Kara told J’onn about M’gann fighting for money in an underground fight club. He became furious that she has allowed herself to be exploited by humans in this way and rushed off to talk to her.
J’onn confronted M’gann about the fight club but she got defensive. She insisted that she has never killed any of her opponents. She also insisted that she is neither interested in remembering Mars, nor rekindling her connection with her old life. She has tried to survive and has moved as far as possible from that life. She told him to go, but she gave her the identity of the tattooed woman, Veronica Sinclair, aka Roulette.
At the DEO, Kara talked with Mon-El, and they bonded over conversation about their parents and how similar they were. Mon-El promised to do as he is told from now on, as he realized that they were not trying to protect him from danger, but rather protect humans from him until he can be able to control his abilities. He also gave Supergirl some useful information. He had seen Draaga fight before, and knew that his right leg is injured, so he favors his left.
J'onn was apprehended by the fight club henchmena and was forced to fight against M'gann. As the two Martians refused to fight each other, Roulette released Draaga to fight them both. The DEO then bursted in to raid the place, with Maggie and Supergirl joining them.
Supergirl ended up taking down Draaga largely thanks to Mon-El’s advice. Thereafter, when the aliens are about to join forces to pounce on her and the DEO, Supergirl then made a speech where she reminded them that humans are not the enemy. The real enemy are Roulette and people like her are, for taking advantage of their fear and insecurity; and keeping other people afraid by portraying them as dangerous.
