Supergirl comes face-to-face with Cyborg Superman when she attempts to save Mon-El from Cadmus.
Tropes in this episode:
- And Then John Was a Zombie: J'onn learns that he's turning into a White Martian.
- And This Is for...: During his scuffle with M'Gann, J'onn says that it's for his family and all the Green Martians that died.
- Bait-and-Switch: The Cold Open leads the viewer to think that J'onn has turned against Supergirl and is trying to kill her, but it turns out to be the real Hank Henshaw fighting her.
- Becoming the Mask: M'Gann doesn't want to die in her true White Martian form, as she sees herself as a human now.
- Berserk Button: Once it's revealed that M'Gann is a White Martian, J'onn goes absolutely berserk, ignoring her pleas that she tried to stop the genocide.
- Big Damn Heroes: Jeremiah unexpectedly returns to extract the bullet from Mon-El's leg and help him and Kara escape Cadmus.
- Body Horror: J'onn is transforming into a White Martian.
- Borrowed Biometric Bypass: The reason why Cadmus takes Supergirl's blood. They need the DNA of a member of the House of El to bypass the security measures in the Fortress of Solitude.
- Brought Down to Normal: Kara intentionally depletes her powers using the solar flare in order to save Mon-El.
- …But He Sounds Handsome: James and Winn are both quick to defend Guardian and his backup. Winn is also very clear that the guy in the van for Guardian is a partner, not a "sidekick".
- Call-Back:
- Lillian mentions the time Supergirl depleted her powers fighting Red Tornado, and forces her to do it again by threatening Mon-El.
- Since Mon-El is the Last Episode, New Character for Season 1, Kara has to explain to him the story about Hank Henshaw after he thought that J'onn was captured as well.
- Clear My Name: Vigilante Man Philip Karnowsky murders a crook that Guardian has just apprehended, the placement of a nearby CCTV camera making it look like Guardian killed the man in cold blood. James has to track down Karnowsky and bring him to justice to clear his own (alter-ego's) name.
- Comic-Book Movies Don't Use Codenames: Philip Karnowsky is never referred to as "Barrage".
- Cruel Mercy: J'onn doesn't spare M'Gann because he has a change of heart, but because he wants to see her rot in prison for eternity.
- Dope Slap: Alex gives Winn one after he tells her that James is Guardian.
- Dying as Yourself: Inverted. M'Gann decides that if J'onn is going to kill her, then she wants to die in the human from that she's chosen, not her original White Martian form. J'onn ultimately imprisons her at the DEO as punishment.
- Evil Sounds Raspy: Hank Henshaw, in contrast to J'onn impersonating him.
- Expy: Phillip Karnowsky is quite similar in both motivation and appearance to Vigilante, who appeared on the episode of Arrow that aired only five days earlier.
- Failsafe Failure: Superman's robot immediately identifies Hank Henshaw as an unauthorized guest, but allows him full access when he dumps Kara's blood on the scanner even though the robot should be able to plainly see that he isn't her and she is not in the room.
- Fire-Forged Friends: This episode is the start of the relationship between Kara and Mon-El.
- Frameup: Phillip intentionally kills his targets after Guardian has fought them, putting the blame on Guardian.
- Gilligan Cut: After speculating that Mon-El is out with some girl and "having fun on Earth," the show cuts away to Mon-El in his cage.
- Go Mad from the Revelation: J'onn does not take the Internal Reveal about M'gann being a White Martian well.
- Gratuitous Greek: Cadmus is derived from a Greek hero known for killing monsters.
- His Name Is...: A variant. When Kara mentions how the Daxam prince sacrificed himself so Mon-El could live, he starts to reveal something to Kara before they are rescued. Despite what he said about coming to Earth Mon-El may have been that prince.
- In Spite of a Nail: Thanagar exists in this universe as well.
- Internal Reveal:
- Supergirl and the DEO finally learn that the head of Cadmus is Lillian Luthor, mother of Lex and Lena.
- Alex learns that James is Guardian.
- J'onn learns M'gann is a White Martian.
- Knight Templar: Phillip Karnowsky is hellbent on killing everybody who (in his eyes) got away with murder.
- Lighter and Softer: The show's treatment of Daxamite lead poisioning is a lot more forgiving than the comics. Mon-El is saved from lead poisoning by removing the bullet from his leg. In the comics, lead poisoning for Daxamites is fatal even if the lead itself is removed; the only cure is a serum created by Brainiac 5, which doesn't exist until the 31st Century.
- Mama Didn't Raise No Criminal: Lillian Luthor's viewpoint and the motivation for her war on aliens is an exaggerated equivalent. Not only does she deny Lex's responsibility for his criminal activities, but she has actually deluded herself into believing Superman, a "false god from an alien planet" as she puts it, is the reason the world sees her son as a villain.
- Motive Rant: Given by Lillian towards Kara, see Mama Didn't Raise No Criminal.
- Mundane Utility: To show that she has her powers back after her brief stint being Brought Down to Normal, Kara heats up the potstickers at the end of the episode with her Heat Vision. She soon after does the same to heat up pizza when Alex thinks it's taking too long in the oven.Kara: A superhero's work is never done.
- Mythology Gag:
- The bars in the Cadmus cell are made out of Thanagarian Nth Metal, confirming their existence in this corner of the multiverse as well.
- The real Hank Henshaw makes an appearance, transformed into Cyborg Superman.
- Lillian Luthor's name comes from the last live action TV adaptation of the Superman mythos. Lillian also alludes to the past, where Superman and Lex were on friendly terms at one point, which could also be a nod to the same series.
- Supergirl makes a reference to Superman having once worked with a vigilante who had tons of gadgets and lots of demons.
- One of the many women Mon-El has been sleeping with is a blonde Valeronian, the same species as Vartox in the comics.
- Mon-El mentions that Daxamites are paired off at birth, and one day you suddenly find out you are mated to someone. A major story arc in Lois & Clark was about Superman finding himself in that exact situation.
- Never Trust a Trailer: A quite expertly done version. The trailer appears to show J'onn attacking Kara, which is quite believable given that he's just had an infusion of White Martian blood with unknown side effects. Then it turns out this is actually the real Hank Henshaw.
- Off on a Technicality: Phillip Karnowsky targets people who managed this.
- Offscreen Moment of Awesome: Kara mentions that her cousin once worked with an unnamed vigilante with tons of gadgets and lots of issues.
- Oh, Crap!: Kara's look on her face when Hank Henshaw No Sells a punch from her.
- Really 700 Years Old: J'onn practices tai chi as a meditation technique, which he learned from a Shaolin monk in the 1800s.
- Saying Too Much: Winn gives away that he knows Guardian personally when his statements on Guardian's innocence are a little too confident. It doesn't help that he's a Bad Liar to begin with.
- Series Continuity Error: Jeremiah mentions that he's been with Cadmus for fifteen years, meaning since 2001. However, it has been established that Kara landed on Earth in 2003, and the mission to capture J'onn where both Jeremiah and the real Hank Henshaw were presumed dead was in 2005, with J'onn's impersonation of the latter happening a month later. The show really needs to work on firming up its timeline.
- Ship Tease: Mon-El asks Winn and James if Kara is mated with anyone.
- Shout-Out: Winn says that he won't survive in prison, having seen every season of Oz.
- Subtle, but J'onn mentions learning meditation from a Shaolin monk in the late 1800s. Was he named Kwai Chang Caine, by any chance?
- Shout-Out Theme Naming: Mon-El's been sleeping with Eve, Darla, and an unnamed blonde third alien (presumably because saying she's named "Buffy" would be a little too obvious).
- That Man Is Dead: Said almost word for word by Hank Henshaw, who now refers to himself as Cyborg Superman.
- Too Dumb to Live: Kara agrees to solar flare (temporarily rendering her powerless) when Lillian promises to spare Mon-El's life. But before that, Lillian lets her out of the cell, with only Lillian and two guards in the room, and Kara makes absolutely no attempt to fight back or escape.
- Viral Transformation: The White Martians weren't satisfied with getting rid of the Green Martians through forced labor and death camps, and had their scientists alter their own blood so it would act as a mutagen. This means M'gann's blood is slowly converting J'onn into a White Martian, and there's no cure as far as she knows.
- Weaksauce Weakness: Daxamites are confirmed to be weak to lead, so Mon-El isn't bulletproof despite being Super Tough otherwise.
- We Have to Get the Bullet Out!: Justified. Mon-El is lethally allergic to lead, so the bullet has to be removed or it would slowly kill him.
- What the Hell, Hero?: Alex scolds Maggie for giving her false romantic signals and getting Alex to admit to feelings she has for Maggie but then turning Alex down, effectively breaking her heart. As in the last episode, her emotional turmoil makes the usually calm and analytical Alex overlook that Maggie is right; Alex has just come out (and is still dealing with what that means), and Maggie doesn't want to complicate matters by leading her into a relationship right away (which would be a rebound relationship for Maggie).
- You Have GOT to Be Kidding Me!: Alex's reaction to finding out James is Guardian.
