A hacker is attacking National City's infrastructure, but there's more to her than a disgruntled citizen.
Tropes in this episode:
- Awesomeness by Analysis: Both Lucy and Winn figure out that Indigo's early cyberterrorism is just a setup for the alien computer to hack into a military general's nuclear access codes.
- Big Damn Kiss: Siobhan gives one to Winn after he tries cheering her up about their messed-up family lives.
- Call-Back: Cat says she knows what it's like to have all your secrets exposed after a computer hack, referencing the events of "Hostile Takeover".
- Can't Kill You, Still Need You: The last guard in the silo tries invoking this, pointing out that Indigo can't turn both launch keys on her own. Unfortunately for him, he's wrong about that.
- Casting Gag: An obvious one as Laura Vandervoot played Kara/Supergirl on Smallville.
- Computer Virus: This episode gives us an extreme version of the trope with Winn's virus. Apparently it's capable of instantly infecting an alien operating system, even though Winn says he created it a few years ago, so it's not even tailored for Indigo.
- Daddy Issues: Winn and Siobhan bond over their personal issues with their fathers.
- Defrosting the Ice Queen: Early in the episode, Siobhan comments how she doesn't talk to men under six feet tall, like Winn. It takes an alien cyber-attack and Winn's kindness for Siobhan to give him a Big Damn Kiss.
- Easily Forgiven: Kara seems to forgive Alex pretty easily when she tells her that she killed Astra.
- Even Evil Has Standards: However nefarious the implementation of Myriad may be, at least it involves Humanity surviving and living alongside the Kryptonians. This is why both Astra and Non found Indigo's plan to wipe out all of Humanity abhorrent.
- Everything Is Online: Played straight when Indigo hacks National City's traffic lights, but averted with the nuclear silo. Indigo has to find a way to get inside the silo physically, because the nukes are not online for obvious security reasons.
- Five-Second Foreshadowing: Indigo calling Winn "fairly clever for an ape" is the first indication that that she's not human, followed almost immediately by her manifesting right through the laptop's screen.
- Freudian Excuse: At the age of 17, Siobhan walked in on her dad and caught him cheating with his personal assistant.
- Give Geeks a Chance: Winn scoring a kiss from Siobhan definitely counts as this.
- A God Am I: Indigo brags about how she can choke Winn to death through a computer screen.Indigo: I am beyond a body. I am beyond time and space. I'll have to do is squeeze my fingers, and your friend dies. I am invincible, I am a god.
- Green-Skinned Space Babe: Indigo discards her blonde human form and reveals herself as a descendant of the alien computer Brainiac.
- Ineffectual Death Threats: Siobhan threatens to kill Winn if he ever tells anybody about what happened between them.Siobhan: You tell anybody about this, and I'll kill you.
Winn: You threaten to kill me a lot. - Internal Reveal:
- Alex confesses to Kara that she was the one that killed Astra, and Hank took the blame for her.
- Kara also finds out that for all her hoping that Astra had a chance of making a Heel–Face Turn, she was still about to kill a helpless J'onn when Alex saved him.
- Winn reveals to Siobhan that his father Toyman Sr. is responsible for the deaths of many people before being sent to jail and his mother left him.
- Alex confesses to Kara that she was the one that killed Astra, and Hank took the blame for her.
- Lame Comeback:Indigo: You know, you're fairly clever for an ape.
Winn: And you, you are freaking me out for an evil blonde computer face. - Mythology Gag:
- Superman leaving the key to the Fortress of Solitude in plain sight but secure (because there are very few entities capable of physically lifting it) was a standard part of the mythology in the Silver Age comics. Furthermore, James stating that the key is made of a "condensed dwarf star" material, weighing in at half a million tons, is lifted straight from All-Star Superman.
- The interior of the Fortress combines the crystal-style architecture that originated in the Christopher Reeve movies with the giant statues of Lara and Jor-El holding up a globe of Krypton that appeared in the comics and various DCAU appearances.
- The three connected circles on Indigo's forehead have been a symbol used by assorted incarnations and versions of Brainiac for decades.
- Inside the Fortress of Solitude we are given a quick look at a ring on a pedestal. The ring has the insignia of the Legion of Super-Heroes, an intergalactic super hero team in the far, far future. In the comics and TV shows, both Clark, as a teenager, and Kara have been members. Given that Clark has a flight ring we can conclude that he has at the very least worked with them. This can also be seen as possible foreshadowing future episodes and characters. It had also earlier appeared in an episode of The Flash during a trip between dimensions, alongside Supergirl herself, to foreshadow the upcoming crossover between the shows.
- Supergirl's boyfriend in the Legion is also a descendant of Brainiac, but he's much more benevolent than Indigo.
- Supergirl being faster than her cousin is something that Jeph Loeb introduced in his run. It also serves as foreshadowing to her easily catching up to the ICBM later in the episode, which in turn makes the whole thing a nice Shout-Out to Superman of the 1978 film just barely catching one of the two nukes he was up against.
- The truck that's about to hit the car in the first act has a register plate with the word "PLASTINO". This is a nod to Al Plastino
, the comic book artist who co-created both Supergirl and the original Brainiac.
- Nice Job Breaking It, Hero:
- Indigo was wary enough of Astra to stay under the radar while she was around, so Alex killing her gave Indigo the freedom she needed to make her move against Humanity.
- Kara trying to convince Lucy that James is a great guy backfires badly, since she relates the story about his father, something James never told Lucy.
- The Nicknamer: Not the cleverest one ever, but Cat calls Winn "Toyman, Jr."Winn: I liked it better when she didn't know who I am.
- Not Quite Dead: Non is able to revive Indigo after Winn seemingly kills her, but she comes back as a collection of limbs on a table.
- Poor Communication Kills: At episode's end, Kara realizes Indigo likely would have been stopped sooner if she'd been willing to pool her information with the DEO, and goes back to working with them.
- Reference Overdosed: This episode includes Harry Potter, Doctor Who, Candy Crush Saga, and more pop culture references.
- The Reveal: It was Indigo who was responsible for Kara's pod leaving the Phantom Zone and Fort Rozz following it out, as she remotely activated the pod's navigation systems and linked the fortress's systems to it.
- Rubber Woman: Indigo stretches both of her arms so she can turn two nuclear access keys at the same time.
- Running Gag: Siobhan threatens to kill Winn if he ever tells anybody what happened between them.
- Shout-Out: Diamond Discretions is an adult affair website and the characters mention how it's like the real-life world's Ashley Madison.
- Shut Up, Hannibal!: Winn's response to Indigo's A God Am I speech, right before infecting her with a virus that nearly destroys her. See Take That! below.
- Take That!: Anybody who's up on computers will know that Windows Vista is a terrible operating system.
- Trojan Horse: Indigo uses the chaos she spread earlier in the episode as a distraction to identify an officer who has access to a nuclear launch facility and can infiltrate via his smartphone. That way, she can access the missile silo when the general does a routine inspection even though it has no external internet connection.
- Tsundere: We see Siobhan behaving this way to Winn with her Ineffectual Death Threats.
- Two-Keyed Lock: The missile silo has the standard setup of turning two keys across the room from each other required for a launch. Unfortunately, Indigo is enough of a Rubber Woman to reach both locks.
