A cultist of Coville brings his journal to Supergirl. Meanwhile, Kara struggles on how to fix her friendship with Lena.
Tropes:
- Adaptive Ability: Pestilence's power allows Reign to formulate antibodies to help fight off the Kryptonite, making it even less effective than it already was.
- Arson, Murder, and Jaywalking: Trying to cheer her up, Alex offers Ruby a ride on a motorcycle, the chance to dye her hair tips blue, a pet cat... and a game of Scrabble.
- Blackmail: The cult threatens to expose James' secret identity to the press unless he gives them Tanya.
- Boom, Headshot!: Olivia does this to Guardian. The helmet protects him, but the bullet is armor-piercing and hits with enough force to crack the helmet in half.
- Brick Joke: While trying to cheer Ruby up, Alex mentions that Ruby wanted to dye the tips of her hair. They do this at the end.
- The Bus Came Back: Olivia, the cult member who turned on Coville, returns and is the head of the cult herself now. Coville himself also comes back at the end of the episode.
- Cheer Them Up with Laughter: Alex suggests to Ruby various activities to cheer her up, with most of them being cool and rebellious while the last one is to play Scrabble. This last one is meant to make her laugh due to the sheer randomness.
- Clingy MacGuffin: The Rock of Utacal fuses to Olivia's hand and won't come off. Supergirl solves this by superheating the rock to burn off the flesh it's connected to, allowing Mon-El to pull it off.
- Continuity Nod: Ruby is still processing the shock of learning her mom is Reign and is still mad at Alex for hiding the truth from her.
- Didn't Think This Through: J'onn thinks that video games might help slow M'yrnn's deterioration. Instead, M'yrnn hears the shooting and has a breakdown, flashing back to the White Martian extermination of his people. Fortunately, a game of foosball with Ruby works wonders.
- Exact Words: Lena told Kara that she wouldn't create anymore Kryptonite without speaking to her about it first. She will still develop other countermeasures against Kryptonians though.
- From Nobody to Nightmare: Olivia went from a random member of Coville's cult, who was actually the first to turn on him, to a cult leader in her own right that nearly becomes the fourth Worldkiller.
- Hates My Secret Identity: Kara bitterly notes that while Lena loves Kara, she now hates Supergirl. And she can't tell Lena the truth because then Lena would just lump her with every other person who betrayed her trust.
- Hostage for MacGuffin: The cultists manage to get video of Guardian unmasked and threaten to reveal it to the public unless Tanya and the book are returned to them.
- Idiot Ball: After Guardian is unmasked while saving Tanya, the cops arrive and train their guns on James. Even though the only people with guns are the (white) cultists and Tanya is telling them that they are the ones that kidnapped her, they still tell the unarmed and not resisting James to surrender and allow the cultists to just run off without even a word. Apparently, keeping everyone on the scene to get statements and investigate isn't a priority.
- "I Know You're in There Somewhere" Fight: Supergirl does this with Olivia, convincing her that she doesn't need to be a Worldkiller to have a purpose in her life.
- Intergenerational Friendship: M'yrnn and Ruby start bonding this episode.
- Jerkass Ball: Lena rebuffs all of Supergirl's attempts to reconcile their friendship.
- Jerkass Has a Point: Lena points out that it is easy for Supergirl to admit a mistake now, after she has been exposed.
- Manly Tears: James when telling the story of having been handcuffed by police at 7.
- Mass "Oh, Crap!":
- Everyone's reaction when they realize that Coville's cult is trying to create another Worldkiller.
- Again, at the end when everybody realizes that Lena's synthetic Kryptonite is losing its effect on Reign; she's like a virus mutating to resist medication. Lena estimates that she'll be too strong to contain within two days.
- Mundane Object Amazement: M'yrnn is amazed by a simple foosball he finds on the floor of the arcade. Ruby introduces the actual game to him and he instantly loves it, amused by his "little man" kicking the ball.
- My God, What Have I Done?: Olivia breaks down crying after she reverts back to normal.
- Neck Lift: Olivia does this to Mon-El once she gets her powers.
- Never Found the Body: Coville's cult assumes he died in service to Reign, but he shows up at their hideout in the final scene.
- Obfuscating Stupidity: As Tanya is delivering herself to the cult, Mon-El hops into their van, acting like it's his Lyft. They bring him along, not realizing his true nature.
- Profiling:
- When the police show up during Guardian's rescue of Tanya, they see James unmasked (though still somewhat obscured by shadow) and assume he was the one who kidnapped Tanya, pulling their guns on him while letting her real kidnappers, who were white members of Coville's cult, run away. Keep in mind that James was clearly dressed as Guardian at the time, albeit with his mask off.
- James reveals that he and his cousins were handcuffed by cops for "trespassing" on the property of a hotel they were staying at, the cops having assumed that there could be no way they could be guests and that they had to be committing a crime. James was a seven year old boy at the time.
- Shout-Out: Winn compares James trying to reveal his identity publicly before the cult can do so with the movie Ransom.
- Smoke Out: James uses a smoke bomb to escape with Tanya when the cops mistake him for the kidnapper.
- Surveillance as the Plot Demands: Invoked rather blatantly, given that the cultists managed to acquire security footage from the parking garage Guardian was unmasked in, but the aesop cops neither had body cams nor thought to check said footage.
- Talking the Monster to Death: Kara manages to talk Olivia down from becoming a Worldkiller, appealing to her previously turning on Coville for moral reasons.
- Teeth-Clenched Teamwork: Lena and Supergirl are still at odds on Lena's tech used to control Reign, as Supergirl notes how it theoretically could be used against her. Lena coldly tells her that she doesn't think about her when she's working.
- There Is No Kill Like Overkill: When they are chased by Guardian, the cultists fire at him with a freaking rocket launcher.
- Truth in Television: James tells Lena a story about a time he and some cousins, on vacation at a hotel, played hide and seek and were terrorized by cops who refused to believe they were guests at the hotel rather than ... some kind of gang of criminal seven year olds.
- What the Hell, Hero?: Kara gives a mild one to James, over telling Lena about her request that he break into her lab. James merely replies that he needed to be honest with Lena. Later, Kara realizes she was wrong and apologizes to James for asking him to do it in the first place.
- Wounded Gazelle Gambit: Olivia comes into James' office crying, asking about the whereabouts of her friend Tanya and telling him that she is in danger. Meanwhile, her accomplices are sneaking in behind him to grab Tanya and she pulls a gun on James once they have her.
