It’s been a while since we dealt with the World Killer threat on Supergirl. The season has been slowly building them up as we have seen Samantha slowly transition into one of the World Killers, strong enough to defeat Kara. We are slowly seeing others, but last week Lana Luthor realized who her employee Samantha was, and had her locked in a containment field for further study.
Keeping it secret from everyone (including Kara and James), Lena’s placed Sam in a medically induced coma after suspecting her of being World Killer. She theorizes that everytime Samantha blacks out, her cells mutate and give her Kryptonian powers as Reign. Lana realizes that enough studying has been done, she needs to talk with Samantha. When she wakes her up, all Samantha is worried about is her daughter. Lena assures her that she’s fine, then she drops the truth bomb on her and what she’s been doing. Naturally, Samantha doesn’t believe one word Lena is saying. Lena won’t let her leave her cell until further tests are done. That’s kind of a bad idea to do to someone with Reign’s powers.
As bad as Reign is, she’s not the big baddie tonight. Instead, Kara and company face a completely different threat, one who they know and love. Everyone is doing their favorite past time, drinking at the local alien-friendly bar and all seems well. However, their fun is short-lived as a Kalanorian female starts a fight and proceeds to tear the place apart beating random strangers. Kara intervenes as Supergirl, but the Kalanorian is even a match for her. Once she finally takes her down, J’onn says that her aggressive behavior is due to her psychic abilities and astrological changes, but he knows something else is shaping.
Last week he discovered that his father Myr’nn’s mind is decaying through a process the Martians call “za-alet.” It’s similar to Alzheimer's disease as he’s now forgetful. J’onn takes his father to the DEO to perform a Martian ritual that will move information from the decayed parts of his mind to the part of his mind that is healthy. Unfortunately, it’s not having good results for others.
Kara, who was impressed with Mon-El’s use of a cape, asks him to train her how to use her cape for offensive capabilities. As the two spar and he trains her how to use her cape, her aggression starts to come forward. The same goes for Winn and another technician at the DEO. Alex trying to break them up also gets angry and physical with the two of them. All this pent-up aggression going on is due to Myr’nn trying to cleanse his mind. Turns out as he’s trying to cleanse his mind, the anger and fear of possibly losing his thoughts and memories are bleeding over to everyone in the DEO, both human and alien. The only people not affected are J’onn and Mon-El (who thanks to 31st Century technology is immune from psychic attacks). Everyone else though starts tearing each other apart. Kara even says some unfortunate truths to Mon-El, about how he was such a jerk to her. Only when J’onn tells his delirious father that he needs help and uses a device to dampen his psychic powers does everything die down. A remorseful Myr’nn’s apologizes to the DEO and Kara takes the first step to hug him.
Elsewhere, Samantha wakes up to her cell trashed. Lena Luthor shows her a videotape of her acting as Reign. On the videotape, Luthor taunts Samantha, and Reign comes out. Faced with video evidence, Samantha breaks down, knowing that she’s responsible for so many deaths. Lena promises to help her. Meanwhile, Mon-El and Kara go flying and notice that the birds are dropping out of the sky. This means the next World Killer Pestilence is coming.
