Sam wakes up in her bed and Ruby comes in when she hears Sam scream. Her mother says that she had a bad dream, and Ruby tells her that she went on a trip the day before. Sam has no memory of the trip and realizes that she slept in.
At the DEO, Mon-El says that it's a long story how he was in the 31st century for seven years of his time. He says that conflict is a constant in a thousand years, and Mon-El organized her and other super-powered individuals to keep peace, and "the Legion" exists because of Supergirl. Mon-El used her as an example of what they could be and what they should do, and Imra tells Supergirl that she gave her life purpose. They warn that there is a darkness spreading in the future, and their team got knocked through a wormhole 12,000 years ago. They went into cyrosleep and set the ship to wake them up when they reached the 31st century, but the torpedo hit the ship and woke them prematurely. Kara invites them to a holiday at her place that night, but Mon-el says that they have to work on repairs.
That night, Kara and Alex serve eggnog, and Winn and Hank over Christmas songs. Hank has Winn play "Jingle Bell Rock" for M'yrnn, who is enjoying hot cocoa. Meanwhile, James and Lena are flirting, and Alex asks how Kara is doing with Mon-El and Imra. Kara tries to laugh it off and asks how Alex is doing, and they both insists that they're not wallowing in self-itty. Ruby ad Sam arrive and Alex talks to Ruby about Supergirl. Lena asks if Sam is okay, and Sam says that she's tired. Sam suggest that Lena kiss James, and Lena insists that nothing is going on between them. Kara comes over and agrees with Sam, and says that she got two good things out of the year: the two of them. She explains that she's never had best friends. Hank comes over and tells Kara that they have to go.
He team arrives at a property outside of National City and discover that someone has burned down large parts of the area. Alex has Supergirl fly up and discovers that someone burned a Kryptonian symbol in a field-wide pattern. Back at the DEO, Supergirl shows the symbol to the Alura hologram. Alura says that the Juru used the symbols on the Kyptonian continent where Earth began. Their god eventually became Rao and Modern krypton was born. The ruling council destroyed much of the records of the supposed superstitions, and the hologram warns that a translation may not exist.
The next day, more of the symbols appear all over National City. James tells his news team to pull people in to cover the story, and Lena asks to talk to James privately. Once they're alone, Lena points out that the property where the symbol first appeared was L-Corp property, and figures that Morgan is responsible. James insists on going with Lena to see Morgan. When they get there, Lena asks Morgan if he knows what the symbol is. She figures that he's behind it, but Morgan denies it. James says that he's there to make sure that Morgan remains, and Morgan suggests that James' dislike for him is more than professional. As they leave, Morgan tries to give them presents.
That night at the bar, Kara and Winn discuss the symbol. They find Mon-El and Imra eating ribs and invite them over. They discuss all-you-can-eat ribs and Winn takes Imra to the bar to try beer. Mon-El and Kara make small talk, and Mon-El figures that he and Imra being there is hard on Kara. Kara says that there's not much to talk about, just as Thomas Coville calls her from prison.
Kara goes to the prison and Thomas quotes religious text about Worldkiller and says that there's so much she still doesn't know. He says that the prophecy he speaks of pre-dates the Book of Rao, and explains that the mark belongs to a devil. Thomas met the forgotten of Fort Rozz, including a disgraced Kryptonian priestess, who told him about the god who predated Rao. The first of three events is the Mark of the Beast, the second is the Work of the Best in the form of many deaths. The third is the Reign of the Beast, and Worldkiller comes to bring the End of Days. Thomas insists that Supergirl's purpose is to fight the new god, and Her rise will come at the fall of the righteous unless Supergirl smites her.
Sam is at in her office watching news about recent deaths when Ruby interrupts and says that they need food for dinner. Her mother says that Ruby will be staying with her babysitter and ruby snaps at her. Sam then apologizes and talks about how they spent one Christmas in a truck stop. She describes how Ruby said it was the best Christmas that she ever said, and how it was the best Christmas for her because they were together. Sam gives Ruby her present: an amulet with Supergirl's symbol. She tells Ruby that they're stronger together and hug.
Sat the DEO, Kara tells the others what Thomas told her. Imra comes in and offers to look through the data they've collected and explains that she's the 31st century version of a cop. She then asks to talk to Kara privately. They go off and Imra says that she knows that Kara and Mon-El used to be together. She explains that Mon-el didn't look at another woman for years until he realized that he wouldn't find a way back. Kara thanks her for the information and goes back to work.
Lena takes James to a contact who has access to Morgan's bank records. James asks where the two of them are going in their relationship. They find another symbol burned in a tower, and a man fires an alien blaster at them. James deflects the blast with his hidden Guardian shield,.
At the docks, the One-Seven Gang is making a drug exchange. Someone takes out the lights and the gangers go for their guns, figuring that it's a trap. A masked woman drops among them, shrugs off their bullets, and easily takes them down. The leader runs and the figure catches up to him and kills him.
At CatCo, James and Lena are trying to identify the shooter. Sam arrives and Lena says that the shooter used to work at a tech conference that Morgan hosts. Sam mutters that Morgan shouldn't be alive. The news runs a story on the One-Seven gang's murders. Sam walks out and removes her shirt to reveal the black Reign costume beneath.
At the DEO, Winn reports that the victims were killed with heat vision. They figure that Morgan hired the shooter and planned to blame it on the other killer. Hank wonders if Thomas was telling the truth, but Supergirl says that the new Kryptonian is a pretender and figures that she can handle her. Kara walks off and Mon-El goes after her. He tells Kara that Imra feels bad for upsetting Kara, and Kara says that she's okay with her. She says that out of the three of them, two will be happy, and says that she's trying to be okay with the situation. However, Kara admits that Mon-el looking at her with no love in her eyes is the worst thing she can imagine and walks off.
Morgan calls Lena from his office and says that he heard about the attempted shooting. The Kryptonian bursts in and attacks the office workers, then looks for Morgan using her x-ray vision. She doesn't see him and flies off, and Morgan emerges from his lead-lined panic room.
James calls Supergirl and tells her what happened. Sue tells her teammates and goes to confront the Kryptonian, saying that they're going to do it their way. Flying over the city, Supergirl burns her own symbol into the CatCo helipad.
On the news, Morgan implies that Supergirl attacked him. James and Lena are watching, and Lena tells James that she owes him for saving her life twice. After a moment, Lena kisses James and then he kisses her back.
Mon-El and Imra are sparring, and Imra playfully attacks Mon-El. Supergirl is watching from the gallery, and Winn and Alex arrive to tell her that the Kryptonian is waiting for Kara at the helipad. As Supergirl walks off, Alex tells her to be cold and Kryptonian so that she can defeat the Kryptonian.
Supergirl flies to the helipad and finds the masked Kryptonian waiting. The Kryptonian says that she is Reign and survived Krypton's death. Reign has been dispensing justice and says that the world has sunken into chaos and sin. Supergirl tells her to surrender, and Reign says that she's as proud as the righteous Kryptonians who feared her makers and worshipped false gods. She tells Supergirl to stand down or join the Kryptonians, and Reign attacks her. they smash through an office party and the office workers flee as Supergirl and Reign fight it out. The two Kryptonians pound on each other, and Supergirl flies reign outside and to a nearby factory.
Reign grabs a pair of cargo containers and shoves them at Supergirl, and Supergirl slams them aside and slams into Reign. They land in back in the city and crash to the street, and continue fighting. Reign manages to take Supergirl down, cutting her forehead, and Supergirl staggers to her feet and renews her attack. She knocks Reign back, and Reign throws a flaming car door at her and then blasts Supergirl away with her heat vision.
Supergirl lands on a rooftop, and Reign lands nearby. She says that she's no devil and Supergirl is no god, grabs her, and drops Supergirl into the street below. Supergirl crashes into the concrete and lies, unconscious. Alex and the others take her to the DEO for medical treatment. As they intubate, Mon-El and Imra arrive. Imra assures Mon-El that Supergirl will be okay.
The next day, Ruby runs downstairs and finds Sam staring out the window. When Ruby calls to her, Sam turns to the girl.
Written by Gadfly on Dec 12, 2017