In this week's season finale, Supergirl and her friends make one last attempt to defeat Reign. A lazy storytelling tactic is used, but perhaps this will lead into a very interesting storyline for Season 4.
Spoiler alert! The following contains full spoilers for Supergirl Episode 323: "Battles Lost and Won." Catch up with last week's recap here.
Picking up precisely where we left off last week, the Dark Kryptonians are hard at work, destroying the planet. Kara and Alura fight together, which is cute; Imra returns to help (we later find out that the beacon had some sort of failsafe that caused the transmission to go through, causing her and Brainy to return); and J'onn and M'yrnn say goodbye before M'yrnn liquefies and saves the planet — killing himself in the process.
The planet is safe. For now. Reign was not trapped in the Earth's core, and instead returns to the Dark Kryptonians who promise to restart the cauldron.
Sam is in the Dark Valley, looking for the fountain. She finds it, but also finds her mom, who encourages her to drink from the right side of the fountain, not the left. Sam is doubtful, but eventually does. This was the correct side to drink from and she is strengthened. She and her mom have a nice bonding moment, then Sam wakes in the DEO. She is floating, and fully superpowered.
Supergirl again refuses to kill Reign — that is not her way. But after everyone — including Alura — tells her that sometimes it is the only way to stop evil, she agrees. A beacon goes off from J'onn's spaceship (triggered by Coville before he died), and Supergirl, Mon-El, J'onn, and Alura head off to fight the Dark Kryptonians. Brainy and Imra follow behind and set up a force field.
Fighting begins, and the Dark Kryptonians are cuffed pretty easily. Then it is up to Supergirl to fight Reign. Reign has her in a chokehold — until superpowered Sam strolls in. She stabs Reign in the back, and it doesn't kill her, but it does release her hold on Supergirl. Sam is knocked out, but it gives Supergirl a chance to throw Reign into the cauldron. As she dies, Reign's laser eyes go haywire and catch both Alura and Mon-El in their path. Both die.
Supergirl is overwrought and blames herself for not sticking to her principles. She grabs Mon-El's ring and demands that the DEO find a disruption so she can go back in time and change the outcome. In other words, she pulls a Superman. (This is the laziest possible storytelling tactic, and annoys the hell out of me.) So instead, when Supergirl sees Sam come in, she shouts so Sam doesn't stab Reign. She calls for the Harunel and sends her, Reign, and Sam back into the Dark Valley. Sam forces Reign to drink the poisoned water, and she essentially evaporates. When Supergirl and Sam wake up, they are back on Earth, everyone is alive, and Reign is gone.
There is almost 20 minutes of denouement in this episode, but the important part is in the last few scenes. Lena gives Alura the Harunel and recipe to make more to take back to Argo. But Lena has a secret. Back in her lab, she calls Eve and tells her they are ready to begin Phase Two of the trials. 48 hours earlier, Kara showed up at the Siberian border, wrapped only in a blanket. I am guessing that while time-traveling, Kara split into two selves... maybe the essence of Reign is now in Siberian Kara. Either way, could this be Supergirl's version of Red Son?
Also in this episode:
- Imra basically breaks up with Mon-El. But instead of staying on Earth with Kara, he decides — with trouble — that that he needs to go back to the future. He can't abandon the Legion but tosses his ring to Kara, just in case she needs him.
- Sam is 100% human now.
- Brainy can't return to the future because, while they saved the future, a distant relative of his is evil and puts all AIs in danger. Winn is the only one who can save them. The little chart he drew last week was found in the future and became the foundation to some of the most groundbreaking tech in existence. Winn was revered for this discovery. By the end of the episode, Winn decides he will go to the future while Brainy remains in the present.
- With his father gone, J'onn decides he is stepping down from the DEO and promotes Alex to director. In her new position, Alex won't have to go out into the field and so she may just be able to adopt that baby.
- James took off his Guardian helmet to reveal his face to a panicked mother, looking for her child. Seeing his face seemed to soothe her, so at the episode's end he gives a quote to a local news outlet, confirming that he is Guardian.