The crossover extravaganza is here, and this one actually included Supergirl rather than just tacking it onto the final 30 seconds!
Kara and Alex, still wallowing in their relationship misery, decided to attend Barry and Iris' wedding on Supergirl Season 3 Episode 8.
For most of the hour, we were treated to fun, light-hearted pre-wedding activities, but then the big day arrived, and everything was spoiled.
So we know we're dealing with evil Nazi versions of our heroes. Kara and Oliver both have doppelgangers with similar abilities, as does Wells as the Reverse Flash.
That's all we really know about these guys so far, but we have three more hours to learn more. In fact, Arrow Season 6 Episode 8 aired directly after Supergirl, moving things right along.
It helps that the heroes managed to take one hostage, and Oliver is not hesitant to find out exactly what he knows.
Will he reveal anything useful or stay silent? Chances are they'll get something out of him, because he's their only lead, and this group is not about to wait around to be attacked again.
We don't know why the Nazis attacked, but we do know that they attacked too soon. They underestimated our heroes, and in the end, mostly thanks to Kara, retreated with their tails between their legs.
If they had done their research, they'd know Kara is no stranger to fighting someone with similar powers to her. She did take on Clark and win on Supergirl Season 2 Episode 22.
So, since we don't know much about these evil Nazis yet, let's go back and discuss the fun stuff leading up to the ruined wedding.
First of all, go Alex!
Sara is the perfect person to help Alex have a night of fun and forget about her misery over Maggie. It's way too soon for Alex to consider a new relationship, but a drunken one night stand at a wedding on another Earth? I think that's acceptable.
Alex may be berating herself, but regardless of your thoughts on the hookup, Kara's reaction to it was priceless!
Alex: What did I do? Do you know what I did?
Kara: Not the specifics, no.
The awkward encounter before the wedding was funny too, especially considering neither knew the other's name, but that awkwardness was gone as soon as the attack happened. They both instantly went into fight mode, and they made a great team.
I have to admit, most of the stuff involving Firestorm was lost on me. Stein is clearly excited about the cure and wanted to help Jefferson Jackson keep his superpowers, but he didn't seem as enthused by the idea as Stein was expecting.
I imagine there's more to the story that will be revealed throughout the next three installments, and Legends fans probably have a better understanding of the background of that plot line.
Also, despite the fact that I don't watch Arrow, I really like Oliver and especially Felicity. It was sad to see Felicity shut down his proposal, and I'm curious why she has an aversion to a legal wedding. If that's the issue though, maybe they can just have some sort of commitment ceremony?
How cute was it that Barry asked Kara to sing? The song choice was perfect too, and a nice call back to the Supergirl/The Flash musical.
You have to give Kara props for being able to learn an entire song the night before the wedding and performing it beautifully.
That wasn't the only call back to previous crossovers, either, as a dominator even made an appearance.
J'onn: Supergirl, identify the threat so we can help you fight it.
Winn: Whatever it is, it came out of deep orbit and it is maaad.
J'onn: So it's alien?
Winn: Well, it's definitely not NASA.
Kara: Dominator. These guys are so last year.
Barry and Kara have a special chemistry that is just so much fun to watch. I'd say I wish we could see them together more, but it's more special when we only get them once in awhile.
They just have such an easy friendship, like they've known each other all their lives.
Barry: What happened with Mon-El?
Kara: What didn't happen? The end of the world.
Barry: Faced that three times.
Kara: Time travel.
Barry: I've been there a lot.
Kara: He's married to someone else.
Barry: Oh. That's...I've got nothing for that, I'm sorry.
Due to the crossover, we didn't get to spend much time on Kara's earth, so this didn't feel like a Supergirl episode, and that was the whole point.
Still. Supergirl fans might be disappointed they have to wait to get more answers on Mon-El's time away and his new wife. This wedding came at the perfect time for Kara, as she was not ready to deal with that revelation yet.
I do have a question though. Being that Kara just spontaneously decided to open the portal and go to the wedding, did she and Alex go shopping for dresses when they got there? I doubt Kara kept that portal open long enough for Alex to run home and pack a bag.
Maybe a shopping trip is why Alex was late to the nail salon?
So, will you guys be tuning in for the rest of the "Crisis on Earth X?" Will Barry and Iris finally tie the knot by the end of it, or will it get pushed back to a later date?
For those of you who may have only tuned in for the crossover, but want to catch up on Supergirl, you can watch Supergirl online and see what you've missing!
Stacy Glanzman is a staff writer for TV Fanatic. Follow her on Twitter.