At City Hall, Adelaide Swanson is handing out cookies. She hands one to the mayor, and after Adelaide leaves he starts bleeding from his nose. More blood pours out and he starts coughing.
At the DEO, Alex examines one of the dead birds and says that she couldn’t find any sign of infection. Imra and Mon-El says that it's an early sign of the Blight, and the disease is 100% fatal and highly contagious. Alex figures that the bird came into contact with Pestilence, and Imra warns that if it gets any stronger than half the city could die. Mon-El explains that the cure is in their DNA, and Imra figures that Brainiac 5 can create a cure, weaponized it, and use it to kill Pestilence before she becomes the Blight. Supergirl insists that they have to find the human side of Pestilence and save her. Imra tells her that it's not how she usually operates but it's extreme circumstances.
A man comes in and Mon-El says that it's Brainiac 5. Brainiac 5 explains that he's wearing a personal image inducer, and deactivates it, revealing his Coluan form. He turns it back on and explains that he thought it would help him fit in when he went out. Winn comes in and realizes who Brainiac 5 is, and says that several major political figures have become sick. Imra figures that Pestilence is responsible, and Supergirl suggests that they deal with the sick victims. Mon-El agrees and says that they'll meet up with her later.
Lena tells Sam what happens when she transforms into Reign, and if they can isolate the factor then they can eliminate it. However, she warns that she has to study Sam as Reign. Lena admits that she has to use pain to trigger the transformation, and Sam agrees. She attaches the electrodes and the force field, and Lena finds herself in a dark valley. Reign is there, and says that they're coming for them.
Supergirl, Hank, and Alex go to the bank where the EMTs are taking out the victims. The mayor, who has a scratch on his hand, tells them what happened. Hank has Alex check the other victims for similar marks. They go off, and Supergirl sees Adelaide sitting by herself and assures her that everything will be okay.
Dr. Grace Parker is examining the victims and says that none of the victims remember being scratched. Alex and Winn figure that the source of the infection scratched everyone and it's no contagious, and Grace asks them to lift the quarantine so she can take the victims to a trauma facility. The agents tell Hank and Supergirl what Grace said, and they figure that Pestilence isn't there anymore.
As Hank orders the transfer, people outside start screaming. The team runs outside and finds Saturn Girl there, generating a force field to quarantine the building. Supergirl tells Saturn Girl to take it down, explaining that Pestilence isn't there, and Saturn Girl lowers the field. She warns that Supergirl doesn't know what she's up against.
Sam wakes up and tells Lena that Reign was there in the dark valley, Lena figures that it's a parallel dimension and Sam's consciousness goes there when she transforms. She admits that she hasn't found what causes the transformation and needs to increase the voltage.
On the cruiser as they transfuse their blood for the cure in their DNA, Imra says that Supergirl isn't taking matters seriously. She tells Mon-El that it's about their mission to save the people of their time, and Mon-El suggests that Supergirl might have the right idea. Imra finishes first and tells Mon-El that he's always been a bit slow.
That night at the DEO, Winn goes through security footage to spot Pestilence, and the Legionnaire manufacture the cure. Alex tells Supergirl that there's a good chance that Imra will come around, but Supergirl doesn't believe it and insists that she doesn't kill. She figures that they can reach the people inside of the Worldkillers, and Alex suggests that Imra needs a little more time. Winn says that he found one person who came into contact with all of the victims: Adelaide and her cookies Supergirl recognizes her from their conversation and flies there. Saturn Girl is standing over the dead Adelaide, and says that Adelaide was dead when she got there. She figures that Adelaide is another of Pestilence's victims, and admits that she came there without telling Supergirl. Hank and a strike team burst in, and back at the DEO Alex realizes that Winn is infected.
When the others get back to the DEO, James joins them and they administer the Legion's cure to Winn. James tells them that the city is panicked about the outbreak, and Hank tells him that their sending the cure to all of the hospitals. Brainiac 5 asks Winn who scratched him, and he jokingly describes Freddy Krueger. Alex figures that the scratches don't manifest until the symptoms do, and the only trace she can find is a mild anesthetic. Hank sends a team out to question the victims, and Supergirl approaches Imra and asks why she went behind her back. Imra insists that she didn't have a choice and explains that the Blight in the 31st century is overrun. She says that she'll kill Pestilence rather than risk that, and warns that she's seen the future and Supergirl fails.
Sam walks through the dark valley and finds Reign there. Reign says that Sam kept her there, and Sam is much stronger than she should be but that will change. She says that Lena is breaking Sam's body and Sam should stop her, and dismisses Sam's life. Reign tells Sam that she's been trapped since Ruby was born and it doesn't have to be that way, and a life of power is there for Sam if she embraces it. She offers her hand to Sam... and Sam wakes up. Sam tells Lena that they have to find another way, and Reign represents her dark side. Lena warns that Sam will be trapped forever if she gives in, and Sam asks for a moment to brace herself.
Supergirl and Hank check on Winn, and Supergirl wonders if she'll get through to Pestilence. Hank says that she has to try, and tells her that he doesn't know what M'yrnn will remember. He keeps trying because sometimes M'yrnn does remember, and he keeps talking so his father can find his moments of clarity. Hank tells Supergirl that she inspires them to find a way to accomplish the impossible every day, and Supergirl thanks him for his advice.
On the cruiser, Imra tells Mon-El that Supergirl didn't listen to reason. He realizes that Imra made her decision out of vengeance, and Imra insists that she's keeping her feelings out of it. Mon-El tells her that she can't keep punishing him when she brought him there, and Imra walks off. Brainiac overhears them and admits that he didn't tell Mon-El about the mission because he never would have agreed to it if he had known. Mon-El reminds him that they took an oath to protect the innocent, and Brainiac 5 insists that they have to kill Pestilence to prevent the Blight from occurring. He then tells Mon-El that something has happened to Winn.
Winn goes into convulsions, and Brainiac 5 says that since Pestilence isn't technically the Blight, he has to modify the cure by using Pestilence's DNA. Alex collapses from the infection and they treat her along with Winn. Imra watches as Supergirl stays with her foster sister, and Hank tells Alex to hold on. Once the others leave, James asks Winn what's going on. Winn says that he's finally made peace with his mother and now he's been infected. He figures that there's no cure, and tells James that he's been reflecting on his life. Winn tells James that he's made some true friendships since his mother abandoned him, and says that he's ready to do great things but it's too late. James assures him that he'll do whatever he wants and tells his friend to get some rest.
James calls Lena and tells her that they need Lena to put her people on it. She says that she's working on it, but asks James not to tell Supergirl that she's close to a breakthrough. Lena assures James that he's helping and says that she's glad that he called. Once she hangs up, Lena turns to Sam and asks if she's ready. Sam lies back and soon finds herself in the dark valley again. She hides from Reign, who finds her and tells Sam that she's seen the power she can have. Sam insists that Reign is nothing but a cancer, and Reign grabs her by the throat and says that she will turn the world into ash along with Ruby.
Sam wakes up and tells Lena that Reign said. Lena admits that she hasn't found a trigger, and Sam says that they need help to stop Reign before she kills Ruby. Sam suggests that Lena call Supergirl or Alex, but Lena warns that the government will lock Sam up and dissect her. She swears that she is the only one who knows how to do it, and promises that she won't let Reign hurt Ruby.
At the DEO, Brainiac 5 tells the others that Winn and Alex spent much of their time in CCTV blind spots. Supergirl suggests that they check Adelaide's social media, which Brainiac 5 hasn't checked. Twenty-four hours before the outbreak, Adelaide brought cookies to a mobile flu center. Grace is in the photo with Adelaide, and they figure that Grace is Pestilence. Brainiac 5 brings up Grace's history and learns that she's a doctor, and Mon-El figures that Supergirl can get through to her. Grace just went to an insurance company, and Supergirl and Mon-El head there while Hank organizes a strike team. Brainiac 5 contacts Imra and says that they found Pestilence's human body.
At the insurance company, Grace prepares to infect the board of directors. She goes into the boardroom and says that they sought out ways not to pay their customers, As Grace prepares to infect the CEO, Supergirl and Mon-El arrive and stop her. The board members run, and Supergirl tells Grace that she's good. Saturn Girl arrives and Mon-El tells her to give Supergirl a chance to get through to Pestilence's human side. Supergirl reminds Grace of her Hippocratic Oath, and Grace reverts back to normal. She says that she saw the truth that there's no reward for being good, and Supergirl tells her that they can stop Pestilence. Grace takes her hand and says that she doesn't want to stop it, and now she gets to choose who dies.
Mon-El snags Pestilence's hand with his cape as she tries to stab Supergirl. She throws him across the room, and Saturn Girl telekinetically throws a chair at her. Supergirl throws Pestilence through an inside window into the lobby, and drops down to block her escape. Saturn Girl telekinetically drops pieces of the balcony on Pestilence, and Mon-El catches a pole that Pestilence throws at her attacker. Supergirl grabs Pestilence and throws her into the wall, but Pestilence laughs and points out that she scratched her attack. As the Kryptonian collapses, Saturn Girl seals Pestilence in a force field and telekinetically throws a dart into Pestilence's shoulder.
Purity drops in and unleashes her sonic scream on the heroes. Once they're down, she helps Pestilence up and they fly off together. Mon-El realizes that Purity made Pestilence stronger, and Saturn Girl points out that the dart has Pestilence's DNA so that Brainiac 5 can engineer a new cure.
Later, Supergirl and Alex wake up, cured of the infection. Hank tells them that Winn has already gone back to work, and Supergirl tells Alex that they haven't got Pestilence yet. Once Supergirl leaves, Hank tells Alex that he couldn't imagine getting through the next few months without her.
Supergirl finds Imra and admits that Imra was right. Imra tells her that she was wrong to try and make Supergirl change, and explains that under Psi's influence she saw her sister. The Blight killed her sister, and figures that Supergirl wouldn't have killed Pestilence even if Alex died. They go back inside and Winn and Brainiac 5 say that they've located Purity's unique frequency... and she's heading to L-Corp.
Lena tells Sam that she's found something, and Sam says that they're coming. Supergirl and the others arrive and see Sam, and Lena explains that she's been trying to cure Sam. Reign takes over Sam's body and Lena paralyzes her with her tablet Purity and Pestilence break in and Purity takes down Supergirl. Pestilence removes the electrodes from Reign, who uses her heat vision on Hank. The three Worldkillers fly away
Written by Gadfly on May 1, 2018