Guardian debuts to lend a hand after a parasite alien drains Supergirl of her power. Mon-El considers a less than desirable new career which then leads him to contemplate his motives. Alex struggles with a new reality.
In Norway, a scientist alerts Dr. Rudy Jones of a frozen wolf from 3,000 BC that is still at a normal warm body temperature. Jones dissects the wolf and is attacked by something inside the wolf corpse.
At the Alien Bar, M'gann serves Mon-El and Kara some Aldebaran rum from Giggles sitting across the bar. M'gann remarks to J'onn that his friends are nice. J'onn says they help him feel less lonely. M'gann says the bar does that for her as well. Kara prods Mon-El about what job he has picked but Mon-El hasn't picked one yet. She insists on letting her train him. They both then get wasted off the rum. Alex enters the bar and catches her sister drunk. Alex spots Maggie and asks her what do about her coming out. Maggie suggests that she come out to her family. Alex thinks it might be a phase but Maggie tells her that it is real. Alex suddenly gets an alert so they all leave.
At the D.E.O., Winn shows them a distress call from Norway's Thorul Arctic Research Station showing scientists being attacked by an unseen creature. Alex and J'onn take a jet up to the station. They find a trail of dead bodies but find Rudy Jones, a lone survivor. They take him back to headquarters. He tells them that he must continue his research into global warming and that they can find him at National City University. As he is leaving, a parasite crawls out of his mouth and through his ear.
Mon-El trains with Kara. Kara easily avoids his punches and takes him down. After they take a break, Kara stresses the need to learn how to use his powers to make a difference. Alex pops in and asks Kara for a talk.
During the walk, Alex nervously tells her about her feelings for Maggie and comes out to her that she might be gay. Alex tells Kara how she is constantly thinking about this and remembers how she might have felt these feelings before when she was younger, believing she's repressed feelings for other girls in the past. Kara asks if she's seeing Maggie, but Alex leaves flustered.
At Dr. Jones's office, he analyzes his blood and determines that he and the creature have become one. Jones's boss walks in and fires him for his beliefs about global warming. Jones reacts violently and kills his boss, sapping the life out of him.
Winn discovers video feed of the attack at Thorul and discovers that Jones was infected and caused the deaths of the other scientists. Supergirl and Alex arrive at Jones's office and find the corpse of his boss. Jones claims they can't stop him and his cause of saving the world. Jones grabs Supergirl and starts absorbing her powers. Supergirl collapses and Alex fires shots into Rudy which have no effect. Rudy breaks down a glass window and leaves.
Winn identifies the parasite and how it feeds on its hosts. James comes into the infirmary and checks in on Kara. James tells him he wants to help, but Kara brushes him off. Winn takes James aside. James demands his suit since Kara nearly died. Winn bluntly tells him that he will know when the suit is ready and that if he were to go out in the field, he would die. James accepts this.
Alex returns to the apartment and tells Kara she feels like she's disappointed Kara. Kara insists that she is okay with Alex's coming out and invites her to sit and talk. Kara apologizes for not making it comfortable for Alex to share this with her. Kara sympathizes with Alex in feeling like being alone and shutting off a part of herself. She reassures Alex that she doesn't have to face it alone. Kara then encourages Alex to talk about why she likes Maggie. Afterwards, they get an alert about an alien attack downtown.
Supergirl discovers that Mon-El is roughing up an alien, Brian, for an unpaid debt. After letting him go, Kara berates Mon-El for abusing his powers for money, saying that it goes against what being a hero stands for. Mon-El accuses Kara of being a hypocrite, claiming that Kara is fighting crime for the attention.
After Kara reports back to the D.E.O., Winn identifies Jones's next target to be Rand O'Reilly, another NC University board member responsible for ousting Jones. Jones confronts O'Reilly in a parking garage but Supergirl arrives and O'Reilly shapeshifts into Martian Manhunter. Jones pushes them away and runs for it, but Supergirl and Martian Manhunter go to stop him. Jones grabs hold of both of them and starts sapping their powers, turning into a purple monster in the process. Alex and a D.E.O. team fend off Parasite and recover the two.
In the infirmary, Alex explains that Kara will be able to recover from light therapy, but that J'onn lost too much blood and needs a blood transfusion. Alex realizes J'onn isn’t the last Martian and leaves.
Winn and James go to the storage room where Winn gives James his new suit. James says that this new identity is who he really is.
Alex finds M'gann at the bar and asks for her help. While M'gann gathers her things, Alex spots Mon-El across the bar. Alex calls Mon-El a coward and that Kara believes in Mon-El's potential. Alex prompts him to stand with the rest of them and leaves with M'gann.
When M'gann discovers that J'onn needs a blood transfusion from her, she tries to get out of it but Alex insists that J'onn needs her help. M'gann accepts and asks J'onn to forgive her.
While riding a limo, Parasite attacks the real Rand O'Reilly. Mon-El distracts Jones and hurls a street sign at him. Parasite grabs him, but a grenade thrown by James, acting as a new vigilante Guardian, frees Mon-El. Guardian uses his shield to block Parasite's incoming punch. Kara wakes up and starts heading towards the battle. Mon-El saves a girl from a thrown car. Kara flies towards a nuclear reactor. Meanwhile, Guardian fends off Parasite. Supergirl arrives and makes Parasite absorb radioactive plutonium, causing him to explode. Kara commends Mon-El and Guardian for showing up to fight. After Kara fails to x-ray Guardian through his suit, Guardian leaves on a motorcycle.
James and Winn commend each other for their efforts. James vows to continue helping people and tells Winn to keep it a secret from Kara.
J'onn wakes up to M'gann sitting by his bedside. J'onn thanks M'gann and tells her to stay until he falls asleep. M'gann notices J'onn's hand shaking.
Alex runs into Maggie at the bar and tells her that she came out to Kara. Alex then kisses Maggie, but Alex senses something is wrong. Maggie tells her that she shouldn't be involved with someone who is recently out and tells Alex she is here as a friend. Alex doesn't take it too well and leaves in tears. Kara finds Alex at her apartment. Alex tells her she made a mistake and that Maggie turned her down. Kara hugs Alex and tells her she is proud of her.
While Mon-El is walking in the street, he happens upon a person coughing. He offers to help him out, but the guy pulls a tazer baton on him and a group of armed Cadmus agents kidnap him.
- The facility Rudy Jones works in Norway is named, Thorul Arctic Research Station. In the comics, Lex Luthor's family decided to change their surname to "Thorul" (an anagram of "Luthor") due to shame caused on them by Lex's crimes and reputation.
- The alien parasite plot of this episode is directly inspired by John Carpenter's 1982 horror film The Thing.
- During the fight with Parasite, Mon-El wears a dark blue jacket over a red shirt. This mirrors the TV show, Smallville, in which Clark Kent would frequently wear a red jacket over a blue t-shirt (or the other way around), as an homage to his classic superhero costume. This color motif on Mon-El's clothes is used for the same purpose on the show.
- At some point during the episode, Winn sits inside a truck marked "Star Spangled Delivery Co.", established in 1941. This is an easter egg to DC superhero Star-Spangled Kid, who made his debut in Action Comics #40 (September, 1941) and was created by Jerry Siegel (co-creator of Superman) and Hal Sherman.
- James and Winn's describing themselves as the "Super Friends" is an allusion to the classic animated series Super Friends, a child-friendly version of the Justice League of America.
- The Cadmus guards uniforms resemble those of the Cadmus Guards in the animated series Justice League Unlimited
|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"|