But there are a couple of running themes in this season which this episode continues to build on.
For one, this growing sense that Kara is pushing people away and becoming isolated was in full force here. From Alex to Mon-El to continued friction with Winn, we see some evidence that Kara is feeling more alone now than ever. (Luckily, there was some easing of this at the end and a return of the super-sisters!)
Another ongoing thread throughout this season has been one of prejudice. Whether alien immigration or Green/White Martian racism to Cadmus' xenophobia, hate and prejudice has been a strong undercurrent in season two. And furthermore, it isn't just seen in the bad guys. J'onn has had to deal with his own hate and prejudice here and in this episode he really moves forward. And this is great, especially in these days.
But, being a comic nerd for some time, the high point was still the super-powered battles. Seeing Supergirl, Miss Martian, and the Martian Manhunter fighting two white Martians was just eye candy!
On to the show. Spoilers ahead!
Alex arrives and teases Kara that her little sister didn't recognize Mon's feelings before the reveal. But then Alex backs out from celebrating Kara's Earth Birthday because she has plans with Maggie to see the band Bare Naked Ladies. (Yes, I am sure there is a double entendre that Alex loved Bare Naked Ladies in college.) It's pretty obvious that Kara is crushed but she puts in a brave face.
Meanwhile, Miss Martian spies Hank outside the bar in the form of a vagrant. She confronts him for shadowing her around town but he says it is because he is worried about the threat of the Whites. It is both creepy and endearing, your mileage may vary. But it is good that he did because a White does arrive and fights the two to a standstill. The white retreats once Supergirl joins the fray.
There a couple of nice touches here. Kara saying 'mind if I cut in' when she joins the fight is classic comic dialogue. And I love that M'gann's fighting form is still as a green Martian.
At the DEO, we see that Kara is still miffed that Winn is doing his Guardian heroics. But I have loved the growth in Winn's character this season. I love that he says he can have a calling too.
But Kara's body language is perfect. Benoist is so wonderful in all aspects of her acting.
He gives her a two hour window to meet him and be brought to Mars.
Before she gives herself up, Hank comes to try to stop her. He talks about how he didn't think he could love again but she has entered his heart. It is a pretty heartfelt scene showing how he has overcome his own bias to see what a wonderful person she is.
Maggie can sense that Alex is worried about Kara's feelings. So before they leave for the concert, Alex heads to the DEO to clear the air.
Alex doesn't want to feel guilty about having fun with Maggie but she knows she hurt Kara. Kara says it was she who was being immature and tells Alex to head out. But it is again clear that she isn't exactly being truthful. The body language is again perfect.
But before Alex can head back out, we see two M'gann's in the building. One is a white Martians. The white and J'onn brawl (a very well done fight scene) but with the lights flickering, the white (presumably Armek) slinks away.
The DEO goes into lockdown, locking the white Martian in the base. But since it can mimic anyone, agents don't know who to trust. This very much felt like The Thing where know one knew who was an alien in hiding. This is tense with different agents pulling out their sidearms and threatening everyone.
And asking personal questions won't matter because Martians read minds. (We do learn that Winn hates the smell of Kara's teakwood and tobacco scented candle. Brilliant!)
And then we get a Thing homage which is a little more on point. J'onn knows that any Martian exposed to an open flame will show their true form. So he has everyone approach a bunsen burner. Even J'onn does it, but only with some very warm words of encouragement from M'gann. She is pretty close to him when she whispers that he has the strength to do it.
Shockingly, it turns out that Winn is actually the White Martian. Another fight breaks out, this time between 'Winn' and Hank. Once again, the White Martian escapes but not before it triggers the DEO's private nuclear reactor to explode.
Okay, this is where things get a little wonky. We learn for the whites to know as much about who they imitate they need to keep some telepathic leak. So Winn needs to be alive and close by. I guess I buy that.
But then the team makes the biggest mistake in these situations! They split up! They need to find the real Winn to shut down the reactor.
Alex and Kara team up and during the sweep Kara opens up to Alex. (The sisters' recent poor communication is shown when Kara doesn't know Alex' hand signals.) Kara only knows life with her sister by her side. She is afraid of being abandoned, afraid of that since Krypton exploded. And she worries Alex will be taken away from her. Negative space in the shot adds a nice layer to this.
But Alex assures Kara that she isn't going anywhere. It is a nice scene. One thing kind of missing this season has been scenes of the super-sisters together. So I liked this.
That is until we see Hank and M'gann come upon the cocooned Winn and ... dun dun dunnnnnn ... Alex! There are two white Martians.
"Alex" says Kara is so dumb for not realizing this wasn't her sister. And then Chyler Leigh gets the chance to cut loose with the most deliciously evil monologue of the episode. Supergirl should know not to use heat vision near the unstable reactor. And it is so sick of having to be so cloyingly sweet to Kara. It wonders if Kara will whine as an attack. It is just fantastic. Delicious.
I would love to know just how much fun Leigh had playing this mean version of her character.
But we get some serious brawling. Kara and her white toss each other around. Kara buzzes around him like a bee until ending it with a fantastic right hook. Meanwhile, M'gann and J'onn both in green form(!) fight the Armek. Armek's speech is horrible. He says M'gann looks like a monster in her 'green skin'. But M'gann says it is beautiful. Again, insert your real life reference to racism here.
The fight is ended when Alex uses her Dominator pistol to defeat Armek. Winn defuses the reactor. The good guys win!
Winn again leaves to head out with James. Alex tries to make the concert. And like last week Kara is all alone. This theme of her pushing people away a bit is going to come to a head.
Later, Kara is alone in her apartment again watching a classic movie Auntie Mame! (Hat tip to @FilmandWaterPod and @Lawyersaregood2 on Twitter for reminding me.) That story is about an orphan being brought into a loving, accepting, but somewhat odd family. Again, it resonates with Kara's emotions much like The Big Sleep clip from last week!.
Alex arrives with the traditional 'Earth birthday' cupcake. There is a very sweet scene where Kara says she felt Alex slipping away (and as someone who missed screen time between these two this season, I felt her slipping away too!) Alex says that she isn't going to leave Kara, ever. But maybe Kara's big birthday plans and feeling so sad is because she has be avoiding her feelings for Mon-El.
That fear of being abandoned or hurt is so deep in Supergirl (something we definitely saw in the Silver Age books) that she is afraid to put herself out. She is worried she'll blow it. The risk is too great.
But if Alex has learned anything recently, it is that you need to be true to yourself. Maybe Kara should take a chance on Mon-El.
Meanwhile, M'gann feels like J'onn is family and more. She is going to go back to Mars to be a leader. She knows there has to be other white Martians who feel that she does. She will mobilize them. The two admit they love each other and do a bond! But she has to go. I guess Miss Martian is off the show. Hope she comes back for the finale!
But the 'show ends with Mon and Kara' tradition continues. Kara heads into CatCo only to see Mon-El and Miss Tessmacher leaving for a lunch date. Just as Kara was getting the confidence to return his feelings, she sees he has moved on. And he is kind of a jerk outright saying 'you rejected me, what was I to do.' Harsh.
I'm not a big fan of the Mon-El/Kara relationship but you can't deny the chemistry between Chris Wood and Melissa Benoist. And my guess is things will ratchet up when the aliens trailing him arrive.
So overall a very fun episode with action sequences and emotional beats. Anything that reminds me of The Thing is usually a good thing and the DEO scenes were great. My favorite slice of the show was probably 'evil Alex'.
This season seems to be gaining great momentum!