We’re recapping Supergirl 3×20 “Dark Side of the Moon,” in which Kara discovers she’s not so alone in the universe after all.
In “Dark Side of the Moon,” numerous characters are forced to reckon with the the question of legacy. Kara and Mon-El, in their search for the black rock that should be able to save Sam/defeat Reign, discover Argo City, a small settlement of surviving Kryptonians — including Alura.
Mother and daughter are, as expected, shocked to see one another. Kara thought her mother was dead, and Alura never expected Kara to find her. The rock that Kara and Mon-El are after, however, turns out to be keeping the atmosphere of Argo City breathable. To give up even a small amount cuts down the time the settlers will have to live.
However, Alura and Kara make the plea to the High Council that Argo City should help Earth because Earth not only took Kara (and Clark) in, but it also has been dealing with the legacy of Krypton’s failures, including the Fort Rozz prisoners and now the Worldkillers.
This is a nice callback to season 1, especially as Kara tells her mother about Astra’s development and death. My heart broke a little as Kara assured Alura that they gave Astra Kryptonian burial rites. Alura also believes Fort Rozz was her greatest mistake, so the idea that the prisoners she sentenced went after Kara is painful.
Another recognizable face on the Council is Selena, the Dark Kryptonian leader of the Worldkillers. It can’t be good that Selena casts the deciding vote to give Kara some of the rock; she claims that it is their duty to correct the wrongs of their past, but it’s clear that having inside knowledge of Kara’s plan to stop Reign will help her evil plot.
Kara and Mon-El return to Earth with their black rock, but not before Kara and Alura part ways knowing that they will see one another again. The existence of Argo City provides an interesting plight for Kara: her found family versus her blood family.
So much of Supergirl‘s core has centered on Kara’s found family on Earth and the love they share. However, much of Kara’s emotional struggle has come from being an outsider; unlike Clark, she remembers Krypton. She knew her family and her people before she was sent to Earth. To have the option to return to that, to rejoin her people and not have to hide anything about herself, would be incredibly tempting.
Does she choose the legacy she has created on Earth, or the legacy of her people, one she has been separated from for years, in Argo City?
Mon-El also helps a child suffering with an illness with some future tech; clearly the show wants us to feel a soft spot for Mon-El, but I still want him to return to the future — where he has built a life! — at the end of the season.
Meanwhile, back on Earth, Alex must look to her background as an assassin tries to kill her. Alex proves her action star bona fides by jumping from building to building to confront her assassin, the twin brother of a Fort Rozz prisoner that Alex arrested.
With the tie to Fort Rozz, this story not only reinforces the Kryptonian legacy that is being debated on Argo but also forces Alex to question her own — can she balance her desires of being a DEO agent and being a mother? Had the assassin killed her, Ruby would have been left without a caretaker. What about a future child she looks after? J’onn gives her support without much advice.
Lena also struggles with her Luthor legacy as she agonizes over whether to overdose Reign with kryptonite; this would kill Reign but also Sam. However, James asks her to consider what Sam would want, and Lena knows that Sam would prioritize Ruby over her own life. Reign taunts Lena, telling her that she is darker than she believes, and this is another reminder that Lena comes from a family of supervillains.
One final tie into the idea of legacy comes from Winn and Ruby. While Alex is dealing with her would-be assassin, Winn is tasked with looking after Ruby. Winn is initially a jerk to her, but he apologizes and the two bond over having parents who tried to kill them.
The episode closes with Reign breaking free of her confines just as Kara and Mon-El return. The fight begins.