Preparations are made for a final battle as the evil Kryptonians begin to enact their plans while Supergirl and Mon-El are stranded on Argo City.

Previously, on SUPERGIRL

After what I thought was a severe misstep last episode, with the show’s preachy stance against gun violence, we get back to what has made Supergirl such a fun show this season: a fantastical battle between good and evil. Supergirl and Mon-El are still stuck on Krypton, after Selena and her cohorts stole J’onn’s shape-changing spaceship car. They head to Earth, where they plan to revive Reign and bring her back to the forefront of Samantha’s personality.

Despite Supergirl and Lena saving Samantha and seemingly ridding her of Reign, she’s not doing so hot at the start of the episode because her true nature, really, is being supplanted. Reign was created by the Dark Kryptonians to bring about a level of destruction. She’s not human, despite Lena’s efforts to make her so, and she doesn’t really have a true Kryptonian physiology, so any of the methods they use to help Supergirl won’t necessarily help, either.

While Lena and Alex continue to work on Samantha, Winn helps Mon-El, Supergirl and her mother Alura find their way back to Earth, using a teleportation portal that Kara’s father, Zor-El, was working on before Krypton exploded. The heroes manage to find their way back to Earth just in time for Selena and her gang to attack DEO headquarters looking for the blood of Pestilence and Purity. The DEO team manages to destroy the blood, so Selena and company use their own to bring Reign back.

They plan to use Reign to terraform the Earth so it will be more like Krypton – basically General Zod’s plan in the 2013 MAN OF STEEL movie. It’s an odd desire, since Kryptonians don’t seem to have any problems living on Earth. In fact, they thrive under the yellow sun. It seems like they just want to wreak some havoc on an alien planet when they could just live on a world where they have “powers beyond reason,” as one of Selena’s followers expresses when they begin their plot.

Meanwhile, at J’onn’s apartment, the Martian joins his father in The Reach, to preserve M’yrnn’s memories before he dies. The father and son put the process on hold, though, when the Dark Kryptonians attack the DEO.

It was good to see the show return to form this week, especially since the season finale is next week. It looks like we’re going to have a pretty big battle before the show goes on hiatus for the summer, with Supergirl having to decide whether she needs to kill Reign to keep Earth safe. Will we see a repeat of the Superman-General Zod scene from MAN OF STEEL? Or will the Arrowverse find a better way to handle the situation?