Warning: The following recap contains major spoilers for Supergirl episode 20, City of Lost Children.
The episode opens with Guardian saving a woman from being mugged, only to have her resent him in the end.
Kara and Lena are seen eating lunch, and Lena tells Kara that she has a new project and partner, but their work is top secret. Their lunch date ends with Lena getting a call from Rhea and leaving.
James and Winn have a talk about what Guardian means to people. James explains that he strikes fear in people as Guardian, whereas Superman and Supergirl inspire people and give them hope. Their day is broken up when a telepathic alien begins attacking civilians. James saves as many people as he can, until Supergirl arrives, stopping a car from flying into a building. The alien is then nowhere to be found.
At the DEO, Alex, Winn, John, and James discuss finding the alien, but they want to rely on Supergirl. James offers his help, but is told that Supergirl can handle it, causing him to walk away in dismay.
Rhea and Lena are seen at dinner. Rhea consoles Lena who is upset because she failed their first trial run. When Rhea leaves the restaurant, Mon-El spots her from across the street.
Guardian breaks up a drug deal, until the alien tells him he can give him the location of the alien that attacked the park. Guardian investigates the woman’s home, only to find a young boy there who is terrified of him. He takes off his helmet and tells the child he won’t hurt him, only to have the child begin to trust him.
Alex is seen with the young boy, and reveals his name to be Marcus, at the DEO trying to convince him to help them find his mother. James believes that the best way to go about the situation is with compassion, but John ridicules him for his idea. The boy then begins to stare at James through the room’s camera system. Alex then realizes James should be the one to talk to him.
Mon-El approaches Winn asking him to check the Earth’s atmosphere for his mother’s ship, to which Winn complies and finds the skies are clear.
Lena is seen once again test-running her project and failing once again. She gets frustrated and tells Rhea she wish she could prove herself to her mother and to herself, by being smarter than Lex. Rhea tells her to think like herself and not about Lex, to which she does and begins to solve the problem slowly.
James brings Marcus to Cat Co. James asks Marcus if he would like to play a game, and Marcus ends up using his telekinetic powers to solve the puzzle. They begin to bond over James’ cameras, and they begin to talk about their fathers. Marcus reveals that his father passed away as he migrated to Earth.
Mon-El visits Kara at Cat Co. and tells her about his sighting of his mother. He says he did not see her after all and says that his mother is gone forever.
Lena and Rhea are seen about to test their machine once more as the scene also depicts Marcus seeing his mother on the news and claiming that she’d never do anything to hurt people on purpose. After the machine is activated, Marcus’ powers begin to activate inside Cat Co., which causes havoc in the office.
Supergirl grabs Marcus, who is slowly destroying the entire Cat Co. building, then he powers down after Lena turns off the machine. At the DEO, they realize that Marcus and his mother are victims. James no longer wants to help in the case because he feels guilty for endangering the people at Cat Co. Kara and the team realize there is an atmospheric change that occurs when Marcus and his mother lose control, which urges Kara to call Lena for help. When the phone rings, Rhea picks up the phone and greets Kara as Supergirl.
Rhea threatens to destroy Kara’s sense of morale because she kept Mon-El from her. After a heated exchange of words, Rhea lies to Lena about who she spoke to on her phone.
James is then seen talking to Marcus. They have a hear to heart talk about their pasts and trusting in people. Marcus admits that he can see his mother, although he doesn’t know where she is exactly. Instead, James lets Marcus lead him and Winn to his mother. They find his mother and other aliens of the same race.
Rhea turns on the machine without warning Lena, causing the aliens to power up. Winn’s power dampener fails due to the amount of aliens there. James attempts to talk to Marcus. Lena attempts to shut down the machine, but cannot. The team realizes that Rhea is attempting to transport something to Earth. She eliminates Martian Manhunter as Supergirl fails to stop the portal from the outside.
James gets Marcus and the other aliens to power down. Mon-El threatens to kill his mother, but in the end cannot. She reveals that she’s transporting other Daxamites to Earth through the portal, to which she says, “Welcome to new Daxam,” as the ships hover over National City.
This episode was interesting to watch. Although, it followed the same plan as most episodes of Supergirl do: An non-major event happens causing a character to feel emotional distress, then the main issue of the episode is introduced. The character the episode focuses on attempts to change the situation in some way, shape, or form, only to fail, be inspired later by another member of the team, then succeed in the end. Although, this episode’s ending differed probably to set up the season’s last two episodes. What made this episode interesting was the development of James as Guardian.
Supergirl airs Monday nights on The CW, at 8/7 Central.