Supergirl Season 03 Finale! Super-powers, super-punching Season 04 clues!

Hello, my Supergirl Superfriends!

It's the penultimate episode of Supergirl Season Three and Selena and the Daughters of Juru have come to Earth in search of the Worldkillers, having trapped Mon El and Supergirl back on the floating Kryptonian city of Argo!

We kick off with the daughters testing their new powers under the yellow sun, with heat vision but with those powers comes the toxicity to Kryptonian rock itself -- the  green kryptonite aaaand the Harun-El. Luckily, new Juru acolyte Thomas Coville is still  on hand to do the witchs' biddings.

Back on Argo, Kara, Mon-El, Alura and Thara find the Daughters of Juru’s plans inside Selena’s dwelling, including maps of Earth and the original creation of the Worldkillers, who were sent to Earth prior to Krypton's destruction. Kryptonian crystals have special properties and, thus, one when activated brings a holographic Selena to life.

Holo-Selena informs our heroes Reign and her sisters, Pestilence and Purity, were designed to prepare Earth for the surviving Kryptonians, doing so through seismic and natural disasters to kill all humanity -- terraforming Earth  for the Krypton. But Selena's message was booby-trapped, leaving Thara injured in the explosion.

Desperate to get back to Earth, Alura takes Mon El and Kara to her father's Zor El's lab  where he had been prototyping a transmat device. There Kara also finds cache crystals identical to those that power Kara's kryptonian hologram device at the DEO. It’s the cache crystals that Kara would use to interact with a holographic version  of Alura for the first two seasons. Once in control, Kara speaking through Alura's hologram relays Selena's plan to Winn and Alex.

With the message delivered, Mon El and Winn work together to get the two transmat devices working in tandem. If it looks familiar, it’s the same device from Season 2 episode nine, Supergirl Lives, in which Roulette was running a human slave trafficking ring and Mon El and Supergirl get transported to an alien planet.

Questions: How was Zor El’s transmat supposed to work if it need a second portal? Also, how are Winn and Mon El communicating not using the hologram? Maybe the transmat?

Back on Earth, Selena and the Daughters of Juru  cast a fire spell using the Harun-El to discover Purity and Pestilence dead. The witch's hope? Resurrection of all three Worldkillers, by blood! Specifically, blood contained in the DEO labs. And their storming of the DEO was AWESOME!

As the daughters split up to find the blood, Alex jumps in to slow them, briefly, not with the electronic portal but with a little trickery. Kara uses the Alura hologram to dupe Vita into opening the portal .

In the nick of time, too, because back at the lab where Samantha and Ruby are hiding out, Alex takes on both Selena and the other witch in my favorite fight moment of the episode - complete with kryptonite bullets and an Alex drop kick that sends both witches through a glass window and down to a level below. Bad. Ass.

Supergirl, Mon El and a newly suited up Alura arrive just as Selena and the witches combine heat vision streams to kill agent Demos. Prepped for a fight, Supergirl tosses Purity and Pestilence’s blood samples to Selena only to return her own heat vision to burn the samples. With that, Selena and the daughter retreat.

But Selena has one last play. By using her own blood, the blood that created the Worldkillers, Selena gives new life to Reign, a Reign seemingly separated from Samantha.

Not so fast, though; as Lena explains in some comic book science-sciencery-scienceing, Samantha and the new Reign are actually locally-entangled. As one grows stronger the other grows weaker. Okay, so this is where is it all breaks down and the writers pull a Deus Ex Machina: Alura mentions mythical fountains in the Dark Valley, where one provides strength and the other weakness. So, if Lena shocks Samantha back to the Dark Valley, she may be able to use the fountains that. Are. Mythical... Sure.

Even more comic sciencery is crammed into this moment, for New Reign is now hurtling down the fire pit flame toward the Earth's core, with the sword of Juru. The seismic activity stops M’yrnn’s death ceremony -- "the Reach" -- so he decides to die not by the Reach, but by shape-shifting with the nexus point at the core of the Earth to stop the terraforming. Again, sure. And I'm all like, 'Can we just solve this all with punching?!'

Our final preview gives us just that, though! With National City crumbing from  the seismic activity and Reign headed to the Earth's core, Supergirl and our Superfriends take on Selena! It’s an ending that makes me wonder if everyone comes out alive. Plus, is that Brainy and the Legion ship??

Super-powers, super-punching and possible season four clues as Season 03 Supergirl concludes in “Battles Lost and Won."