Lena and Brainiac work to purify the atmosphere of kryptonite while Mercy and Agent Liberty make their next move.
Tropes:
- Almost Dead Guy: Fiona has enough time to share a few words with Manchester before she expires.
- Armor Is Useless: The armor Supergirl wears has to dedicate all of its power to filtering the Kryptonite out of her system and it doesn't take many hits for it to cease functioning.
- Asshole Victim: Mercy and Otis were both xenophobic psychopaths who cheerfully murdered innocents, human and alien alike. Nobody is especially sorry to see them killed by the Hellgrammite. Even in-universe, their own allies aren't upset at their deaths, although Jensen starts panicking about the loss of their resources.
- Badass Longcoat: Manchester Black, true to the comics.
- Bad Boss: After the False Flag Operation falls apart, Agent Liberty subjects Jensen to an alien parasite.
- Bad Guys Do the Dirty Work: It's ultimately a Hellgrammite criminal who ends up killing the Graves siblings (one who they psychically enslaved).
- Believing Their Own Lies: Mercy tries to convince Alex of the righteousness of their actions, and that the aliens are somehow at fault, despite them being brainwashed into attacking civilians by her side.
- Bittersweet Ending: The good: the attack on the fair was stopped, Mercy and Otis are dead, and the atmosphere has been purged of Kryptonite. The bad: Fiona still died from her injuries, and despite her pleas, Manchester is out for blood in the aftermath, while Agent Liberty is undaunted by this defeat and the mysterious clone of Kara is "training" for some unknown purpose.
- The Bus Came Back: The Hellgramite from Season 1 returns.
- The Chains of Commanding: Alex is under some serious pressure from all her responsibility as the director of the DEO, and later almost breaks down crying.
- Chronic Hero Syndrome: Even when in a suit that is just barely keeping her alive and from harm, and being explicitly ordered not to, Kara just can't help herself and jumps into action regardless.
- Continuity Nod:
- When Mercy kills a DEO defector, Jensen says that he thought the Children of Liberty didn't kill humans, echoing Agent Liberty's words from the previous episode. Jensen clearly has a short memory; Agent Liberty tried to use the quoted line to talk Otis and Mercy out of killing him.
- In the preceding episode, Ben Lockwood praised Guardian as a "human hero"; in this episode, other Earth First proponents praise Guardian's actions the same way (the comment "Guardian of Liberty" implies that Lockwood might even have had a hand in this).
- Defiant Captive: Both the Kopy and the Hellgramite towards the Children of Liberty.
- Dirty Coward: The captive Hellgrammite derides Agent Liberty's rhetoric as nothing but "scary words from a coward in a mask". Lockwood takes his mask off, to prove he's not afraid, but since he's still spouting rhetoric to two aliens who are shackled, helpless, and totally at his mercy, it doesn't exactly have the desired effect. He also notably stays far away from the actual operations, unlike Mercy, Otis, or even Jensen, who are front and center.
- Disposable Woman: Fiona's purpose in the story is solely as a tool for the Children of Liberty and a means to drive Manchester and J'onn's personal storylines.
- The Dog Bites Back: The Hellgrammite spikes Mercy and Otis once he's free from Jensen's control.
- Dropped a Bridge on Him: Otis and Mercy are both killed with little fanfare after being built up as major villains.
- Ear Ache: The final scene has Agent Liberty place the parasite on Jensen. It crawls into his ear.
- "Eureka!" Moment: When Lena told Brainiac to calm himself by shoving his feelings in thousands of imaginary boxes, it gives Brainiac the idea to use thousands of nanites to clear up the Kryptonite in the atmosphere.
- Even Evil Has Standards: Jensen, like Lockwood before him, is not happy about Mercy and Otis murdering humans.
- Evil Cannot Comprehend Good:
- In the aftermath of the attack on the police station, Agent Liberty averts this; unlike Mercy, he recognises that attacking the police, who face danger all the time, won't foster fear of aliens the way they want it to. He suggests making people afraid for the lives of their children, speaking from personal experience.
- Mercy asks Alex why she's protecting Supergirl, and aliens in general. Fantastic Racism aside, Mercy can't seem to wrap her head around the idea that Alex and Supergirl might actually be friends.
- Evil Is Petty: Otis stomps on a child's Beebo toy just to be a dick.
- Exact Words: Otis tries to brush off falsely reporting Supergirl as dead by saying that she was never "confirmed" dead. Unsurprisingly, this doesn't appease Agent Liberty.
- False Flag Operation: The Children of Liberty use controlled aliens to attack humans in an attempt to make humans turn against the alien population.
- Hero with Bad Publicity: Played with; James' extralegal outing as Guardian actually received a positive response from law enforcement, with there even being talk of him being deputised. Unfortunately, the pictures of Guardian, a human, fighting aliens struck a chord with the Earth First movement; they happily praise Guardian as a human hero taking the fight to the "roaches", much to James' disgust. He's getting nothing but good press, but the kind of people praising his efforts is not the kind of praise he (or any genuine hero) wants.
- He's Back!: J'onn finally jumps back into action.
- Humans Are the Real Monsters: Demonstrated again by the Children of Liberty; all of the harm in this episode is caused by them as they try to convince the public that Aliens Are Bastards.
- Hypocrite:
- Mercy guns down a DEO agent who assisted them, then Otis casually shrugs off Jensen's objections that "we don't kill humans" by saying that the dead man wasn't human, he was "loose ends".
- Agent Liberty unmasks himself to the Hellgrammite to dispel any notion that he's a coward. He does this while the Hellgrammite and Kopy are still shackled and harmless, and proceeds to place them under mind control to make them even more harmless. The only way he isn't still a "coward in a mask" is that he took off the mask.
- The Children of Liberty use alien parasites and an entrapped alien to further their goals. They also deliberately target humans to cultivate fear of aliens.
- In Spite of a Nail: Earth-38 may have no versions of Green Arrow or the Flash, but they do have Beebo.
- It's All My Fault: Both Alex and J'onn blame themselves for everything going wrong this episode. Alex for her flawed leadership, J'onn for initially refusing to help Kara because of his new pacifist way of life.
- Killed Mid-Sentence: Mercy is skewered by the Hellgrammite as she goes off on yet another xenophobic rant.
- Manly Tears:
- Brainy of all people starts to cry for Kara.
- Manchester, after Fiona's death.
- Me's a Crowd: Kopy can duplicate himself, with each duplicate able to do the same.
- Moral Myopia: The Children of Liberty seem to believe that forcing mind-controlled aliens to attack people proves that the aliens are the monsters, not them. Mercy even has the gall to say that people need to fear aliens, "even if we have to sell it to them".
- Mythology Gag: At the end of the episode Manchester Black wears a shirt with the Union Jack on it, a nod to his famous chest tattoo from the comics.
- Nice Job Breaking It, Hero: While James going out as Guardian did end up helping people in the climax, the optics of a human superhero fighting aliens in this political climate only ended up emboldening the "Earth First" movement, particularly with Agent Liberty to help manipulate the PR by blogging about it in his civilian guise.
- Not Quite Dead: Fiona is being kept alive so she can be used to control other aliens. The stab wound is still quite fatal, however, and she dies shortly after Jensen runs off with the parasite.
- Not-So-Well-Intentioned Extremist: This episode firmly establishes the Children of Liberty in this territory; they mind control aliens to attack innocent people in the hopes of "proving" that people should be afraid of aliens. All they actually prove is that they care more about xenophobic rhetoric than innocent lives.
- O.O.C. Is Serious Business: Brainy, see Manly Tears above. Lena is absolutely flabbergasted. He responds that he's techno-organic, not an emotionless robot, though he is still caught off guard.
- People Puppets: Using a parasite and Fiona's telepathy, the Children of Liberty are able to control aliens remotely.
- Pragmatic Villainy:
- Agent Liberty disapproves of Mercy using the enslaved aliens to attack a police station. He doesn't care about law enforcement officers getting killed; he just thinks it was ineffective. If anything, the tactic he suggests is even worse.
- Mercy tells Otis off for going out of his way to harass a kid for no reason because it's likely to draw unnecessary attention to them.
- Race Lift: Manchester Black is black here; in the comics, he is Caucasian.
- Real Life Writes the Plot: When Season 4 began shooting, Melissa Benoist was on Broadway in the musical "Beautiful". Thus, this episode was the first shot, with Benoist adding voiceover in post, as well as close-ups of her face added in. When her run ended, she joined the rest of the cast in Vancouver, starting with filming the scene where Supergirl takes the new suit's helmet off.
- Reformed Criminal: Manchester used to be a part of a hooligan group, until Fiona convinced him to become better. With her death, he seems to be reverting to old habits for the sake of revenge.
- Rousing Speech: Alex gives one to the DEO, hoping to convince any faltering agent to do the right thing and not give in to hate.
- Screw the Rules, I'm Doing What's Right!: Despite the danger of facing additional charges, James finally decides to go out as Guardian and help Supergirl.
- Talking Is a Free Action: Averted with Mercy's death; the Hellgrammite spikes her while she's distracted delivering a xenophobic rant to Alex. Talking is most certainly not a free action.
- Tragic Keepsake: Manchester Black has Fiona's engagement ring around his necklace.
- Tranquil Fury: Lena, in a totally calm voice, makes it clear that she is absolutely furious at her technology being used for evil yet again.Lena: I could murder someone.
- Would Hurt a Child: Agent Liberty believes that the best way to turn people against aliens is to make them afraid for their children. Therefore, the Children of Liberty sic their mind-controlled aliens on a city fair full of them.
- Your Approval Fills Me with Shame: James is not pleased to find out the Children of Liberty are praising him as a human hero and using the image of Guardian to promote their beliefs.
- You Have Outlived Your Usefulness: The agent that helps Otis and Mercy raid Site B is killed by them to cover their tracks.
