This article contains spoilers for Supergirl season 3, episode 22, 'Make It Reign'.
Being the penultimate episode of Supergirl, this episode needed to set up a lot for the finale — and it did a remarkable job, bringing together almost all of the elements that have been used in the series so far this season.
The episode starts with Serena (Anjali Jay) and two other Kryptonian witches from the Sisters of Juru, getting to Earth and with Thomas Coville (Chad Lowe), using the black kryptonite to do a ritual to summon Reign. However, they can't fully do it because they are missing the blood of Pestilence and Purity. But that's okay — they have samples of both at the DEO.
Meanwhile Kara (Melissa Benoist) and Mon-El (Chris Wood) are stranded in Argo City without a way to communicate with Earth… and Serena left behind a trap that didn't kill them, but did injure Kara's childhood friend Thara Ak-Var (Esmé Bianco).
On Earth it's time for M'yrnn (Carl Lumbly) and J'onn (David Harewood) to begin "The Reach", a ceremony where memories are passed on from those Martians about to die. M'yrnn says goodbye to Alex (Chyler Leigh) before they begin. And Winn (Jeremy Jordan) has started making the non-lethal weapons by creating a belt buckle that gives off a magnetic forcefield. He has Demos (Curtis Lim) hit him to test it out. He then gives one to Demos, which couldn't possibly be a setup for later.
Alure (Erica Durance) takes them to a transporter platform that her husband had been working on. Kara figures out that she can contact the DEO through the crystal hologram of her mother back on Earth and gets a hold of Winn, who yells for Alex. J'onn and M'yrnn begin the ritual, and we see a lot of the recent memories flowing around them. Winn and Mon-El figure out the transporter, knowing that it will be a one-way trip. The beacon Mon-El had made to summon the Legion got broken in the trap/explosion. All the while Sam (Odette Annable) is getting weaker, and Alex and Lena (Katie McGrath) are trying to help her by charging her up with yellow sunlight, but it's not working. And before Winn can get the portal open, the three Kryptonian Witches attack.
Alex takes them on with her gun Winn made while Demos is sent to destroy the blood in the lab. Winn uses his force field to protect him from one of the witches, but still gets knocked out. Kara uses the hologram of her mom to trick one of the witches to open the portal, allowing her, Mon-El, and Alura to come through. Alex does a pretty good job of fighting off two of the witches, but finally all three go after Demos, who uses his force field belt to protect him long enough to get the blood to Supergirl before being blasted by three heat rays. He dies.
Supergirl thinks she is destroying the blood, but Serena gets enough of it for the ritual and they vanish. Winn is devastated by Demos' death. Lena is still having no luck helping Sam and with the blood Serena is able to summon Reign, give her the special sword and send her to the Earth core to start terraforming the planet to kill humans and make it a new Krypton. (This must be the first page in the Evil Kryptonian playbook.) The Earth starts shaking with a huge earthquake, that brings J'onn and M'yrnn out of the Reach. Everyone meets up at the DEO and create a two prong plan. They're going to send Sam back into the Valley of Juru to try and make Reign weaker while M'yrnn is going to be taken to the cause of the disturbance so he can meld with the Earth and get it to stop tearing itself apart. This will kill him. But they have a plan.
This episode was a bit all over the place because it needed to be, but still snuck some good emotional beats like M'yrnn saying goodbye to Kara, James trying to console Winn, or Alura asking about Kara's feelings for Mon-El. These moments kept the episode from feeling like just a setup for the finale.
I would've loved to see them take an episode to explore the Reach, showing us a bunch of the history of Mars, the war with the White Martians, and whatever else M'yrnn had in his head. It feels like a missed opportunity to really explore the Martian aspect of the series.
It was really nice to see Alex do well against the two Kryptonians. Her experience and tech make her a bit more of a match… a la Batman. This season has some bumps along the way, but this episode helped pull together a lot of the elements and line it up for a nice, clean ending.
The trailer shows that everyone gets involved and we get the return of Brainiac 5 (Jesse Rath) at least. Hopefully Saturn Girl (Amy Jackson) and maybe one or to other Legionaries come with him. And the question of whether they will kill Reign comes back up, which is kind of weird since she's no longer Sam. Is there that strong of a reason not to kill her?