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For the Superman & Lois episode, see "O Mother, Where Art Thou?".
"Lex and Lena Luthor, teaming up to save Superman's best pal. What would Mother think?"
Lex Luthor to Lena Luthor

"O Brother, Where Art Thou?" is the fifteenth episode of the fourth season of Supergirl, and the eightieth episode overall. It aired on March 17, 2019.




Special guest star[]

Guest starring[]



Four years ago in Metropolis, Lex has bound Lena to a seat, turmoil unfurling all through the city in view of his calamitous arrangement to execute Superman. Demanding that he, not Superman is the Man of Tomorrow, Lex is at last arrested. In the present, a helicopter conveys a sick Lex to Lena at her home. In the mean time at CatCo, James lies passed out on the floor of his office, yet his shooter utilizes the destress signal on James' watch to alert Supergirl. The shooter is gone when she shows up to help dying James.

Lex has been discharged from jail and into Lena's custody since he's dying from cancer caused by kryptonite poisoning. His sole chance at survival is Lena's Harun-El tests. Eve comes in to tell Lena about James' current. At the medical clinic, we discover that James was hit in the spine. J'onn appears and accuses Manchester Black for the assault on James and becomes more resolved to stop him. With James' circumstance still critical, Alex talks with Lena and attempts to persuade her to utilize the Harun-El to save him. Lena is hesitant, however has a thought of who might be able to help her.

J'onn chooses to follow Manchester and Kara chooses to go with him, misleading Alex that she's going to deal with things at CatCo. The pair discover Manchester where M'yrnn died and Manchester has some way or another gotten to the Staff of Kalar.

Lena, urgent to support James, informs Lex regarding the circumstance and requests his assistance because of his aptitude about kryptonite. Her objective? Separate the superpowers part of things that she's been working from the corrective perspective. While Lena attempts to settle things, those holding up at the hospital battle with James' circumstance. Nia & Brainy begin to accuses themselves, everybody cries. James has been placed in a medically induced coma, and when Alex endeavors to settle on choices for his current state, she's rejected as no one but family can do that. Exactly on time, James' sister Kelly shows up, giving Alex, Nia, and Brainy family visitation rights.

James' condition deteriorates. He has inner bleeding and needs surgery which Kelly supports. Secretly, Alex informs her concerning Lena's serum, however Kelly needs to do the medical procedure as she's stressed James would kick the bucket also doesn't fully trust in Lena since she's a Luthor. With the clock ticking on James' life, Lex and Lena test the Harun-El on a malignancy ridden heart. It works. At this point is when Lena hears that James is undergoing the surgery, however, she's furious about it, yet Lex advises her to go to him.

At the emergency clinic, Kelly and Alex bond, Kara and J'onn appear, as do Lena and Eve. Brainy and Eve battle with their feelings about the James circumstance and wind up kissing similarly as the lights glimmer. The lights are glinting at Lena's home, as well. At that point, J'onn understands that Manchester is at the dam and meddling with the force. At the point when the force goes out while James is in medical procedure and the generators don't kick in, Supergirl and J'onn follow Manchester.

Urgent to save James, Kelly consents to Lena's serum. Lena goes into the operating room, tells the surgeons and nurses to depart. She infuses James with the serum and he quickly starts to mend and awakens. At the dam, J'onn and Manchester battle with J'onn at last defeating Manchester with the staff. He gathers Brainy's taken Legion ring. He and Supergirl depart the dam.

With James saved, and friends and family surrounding him, Lena sees something wrong about a light. J'onn battles with what he's done and reveals to Kara he isn't a man of peace anymore. Brainy chooses, quoting Keanu Reeves, that he and Nia can't be together. Back at home Lena deduce that James requiring the serum was all apart of Lex's master plan- which he concedes, including that he had James shot. Lena will not give Lex the serum yet she's to late. Lex as of now took it; the D.O.C. guard is reveled to be an extremely alive Otis Graves and Eve strolls in with a gun, having been working for Lex the entire time.

Lex and Otis execute the rest of the watchmen and police and break in the helicopter just for Supergirl to fly into their way. Lex proclaims it's pleasant to at long last meet her.

J'onn recovers Brainy's ring, however leaves Kara to offer it to him.

Kara reveals to J'onn she will remain with him regardless of what way he picks.

Lex was behind Lena working with the DEO on her serum.




  • The episode's title is a reference to a fictional book of the same name in the 1941 film Sullivan's Travels.
    • The title of this episode is also a reference from a 2000 film of the same name by Coen brothers, about the convicts who record a song in the depression era and become famous. The movie also draws a lot from the epic poem The Odyssey by Homer.
  • In the flashback at the beginning, Lex turned the sun red in a bid to de-power Superman, a reference to The War of the Superman storyline in 2010, when he briefly turned the sun red to save Earth from an invasion of hostile Kryptonians.
  • Lex's act of creating an earthquake is a reference to the original Superman (1978), where Luthor's master plan was to use the quake to sink the west coast and turn the near-worthless desert real estate he'd bought up into a valuable water-front property.
  • Lex having inoperable cancer after injecting himself with Kryptonite is a reference to the original comics, where he discovered that Kryptonite radiation was deadly to humans (if not quite so fast-acting as it is with Kryptonians) after he began wearing a Kryptonite ring to keep Superman at bay and later developed cancer.
  • Brainiac-5's contention that he usually gets along so well with machines may be a reference to his creation, in the DC comics, of COMPUTO, a sentient machine which became one of the greatest adversaries of the Legion of Super-Heroes.
  • While looking at a portrait of Lillian, Lex mentions how her eyes seem to follow one around, the same observation Mrs. Queller makes to Alex in "Shelter from the Storm".
  • It is implied Lena's mother was Irish, another nod to the former's actress, Katie McGrath, being Irish.
  • Supergirl uses a pun when she says "Damn it!" while repairing cracks in the dam.
  • The flow of the season's story completely changes with Lex brought in. The original premise was alien bigotry. It now changes to focus on him and his schemes, with the Children of Liberty largely forgotten and The Elite being reduced to a one-off villain group.
  • Eve saying that her eavesdropping is a nasty habit may be a reference to how her name is Eve.
  • The scene with Lex leaving his mansion to the tune of "Eine Kleine Nachtmusik" could be a reference to Superman IV: The Quest for Peace, where Lex was fond of whistling that tune in the penal colony.


  • There's a factual error in Lex's citation. Epicurus lived between 341–270 BC - making his statement over 2000 years old instead of ~280.
  • James' doctor tells Alex, Nia, and Brainy that they cannot see James because they are not family. Yet when a perfect stranger arrives and states she is James' sister, the doctor believes her without asking her for any ID.
    • However, it is possible she was simply asked to sign information on this fact later.
  • At 3:14, the helicopter ambulance has the registration C-FTHZ. The C indicates the helicopter is registered in Canada where Supergirl is filmed. As the series alleges to take place in the US, the registration should begin with N as for all aircraft registered in the US.