Supergirl returned to a tour de force performance from Jesse Rath in “The Bottle,” an episode which thoroughly explored Brainy’s motivations while also directly addressing the events of Crisis On Infinite Earths. Unfortunately, it also fell back on tired tropes in order to break up a couple the show had already been doing great disservice to.

With National City now firmly implanted in Earth-Prime and Lex Luthor (Jon Cryer) having made himself the hero of the universe, Supergirl was naturally set to be the Arrowverse show most affected by the latest crossover. Kara (Melissa Benoist) spends the early parts of “The Bottle” still reeling from the changes, but thankfully for her there isn’t much explaining to do because every relevant character has been brought up to speed thanks to either J’onn’s (David Harewood) mind-melding or Lex’s deals with the Monitor.

Sisters on every Earth.

This is a minor complaint in and of itself, since Kara having to navigate a world where Alex (Chyler Leigh) deeply believes Lex is a good guy or where Lena (Katie McGrath) is newly ignorant of her best friend’s lies would have been an interesting obstacle. But since removing that fodder for a good story made way for Brainy to take the spotlight for once, it’s not hard to forgive. Not to mention that I doubt anyone wants to have to live through Lena being betrayed all over again.

But back to Brainy, there’s two of him now! Or maybe make that five. “The Bottle” purports that the other Brainiacs of the multiverse were all connected to the Big Brain and therefore managed to make it out of the apocalypse, although they are still left without their respective planets. Only now, it seems they are being targeted and taken out one by one by a mysterious force that our Brainy must stop.

Rath is superb at differentiating the characters and making his scenes with himself (as well as one female Brainy) humorous without going over the top, and Supergirl indulges itself in a little comic book backstory that readers can guess at based on the title of the episode. Yes, “The Bottle” does indeed refer to one of the Brainiacs having bottled his planet to preserve it from destruction, only now he will end up destroying Earth-Prime if he opens the bottle here and now.

This turn of events leads to a particularly touching moment in which Brainy reveals his mother’s similarly maniacal plan and how he fears becoming like her, which explains the reason for his three dots – they’re actually inhibitors. As Kara is the one he first confesses the story to, Karadox shippers may see light at the end of the tunnel for their comic canon couple. But Nia (Nicole Maines) is also along for the ride, and she mercifully plants herself in the be-yourself camp instead of previous confused moments of suggesting that Brainy needs to change. Presumably those were writing mishaps rather than intentional character choices, and this time around Nia promises Brainy she’ll love him no matter what – and as Kara said, those who love him will keep him from anything dark-sided.

Break up with your girlfriend (yeah, yeah) because I’m bored.

Brainy does un-inhibit himself, and therefore turns green in a fun bit of retcon, in order to save the day. This happily means that another Earth may have been saved, and is just waiting for the right moment to be unleashed. On the other hand, it also means that a fellow Brainy has seen an Earth where Lex was in charge, and she has the solution for Brainy to keep everyone safe. The steps are as follows: work with Lex, tell no one, and break up with Nia because you have to be alone except for the connection to the Big Brain for…. reasons. Don’t think it needs to be stated how unnecessary of a breakup this was, but it has been stated for the record anyway.

Speaking of Lex, though, he spends “The Bottle” trying to convince Lena to work with him on her Non-Nocere plan as well as on finding Leviathan in Earth-Prime. Lena is at first torn between Supergirl’s offer of a partnership and her snake of a brother’s, but a combination of Lillian’s coaxing and Lex wearing the Truth Seeker push her over to the Luthor Coalition, though, and now she’s complicit in whatever he’ll be doing – except she thinks she can control him. Ironically, William (Staz Nair) is convinced of the Luthors being in a league of evil despite having none of his alternate memories back, and it’s only Kara vouching for her bestie that makes him back down on one of the family members.

“The Bottle” sets up a pretty intriguing battle between the Luthors and the DEO for the back half of the season, but it’s shame that Supergirl still doesn’t seem to know how to write a complicated romance without just ignoring or breaking up the pairing.