Crisis on Infinite Earths merged all of Arrowverse's alternate worlds, and it looks like Supernatural is following suit by destroying the different worlds in its own multiverse. Yeah, this sounds downright biblical.

Monday's spring premiere, titled "Galaxy Brain," saw Chuck (Rob Benedict) travel to Earth-2 to rant about all the ways in which Sam (Jared Padalecki) and Dean (Jensen Ackles) challenge him. As much as they are a thorn in his side, they're also his greatest creation. Chuck is obsessed. His self-indulgent monologue to a young salesman at RadioShed leads him to a conclusion only Thanos would appreciate: cancel all the other worlds and focus on the original copy. In other words, he's going to destroy every other universe except for Earth-1.

Back at the bunker, the boys contemplate Jack's (Alexander Calvert) deal with Billie, aka Death (Lisa Berry), to eat angel hearts in order to gain enough strength to kill Chuck. Friendly reminder that Jack is currently operating without a soul, which makes him a liability in Sam's mind. Even Cas (Misha Collins) is concerned about Billie, but he's putting his faith in his adopted son. Dean also believes in Billie's plan, and it's only Sam who remains skeptical about the whole thing. But as Dean aptly puts it, Jack taking on God is the only plan they've got right now, so he's just gonna have to trust Billie.

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Jack prays to Billie, who is busy and sends a reaper in her place to make sure he follows her rules, which means not using his powers until he's ready to take on Chuck. Overhearing their conversation, Sam ignores Jack's lie about his private chat with the reaper to assure the young Nephilim that he and Dean are there for Jack. Also taking the time to bond are Cas and Dean, who share a bourbon while burying their season-long tension. But the moment is interrupted by a call from Jody Mills (Kim Rhodes), who's been kidnapped.

The Winchesters find Jody tied up and are immediately attacked by Kaia's evil doppelganger (Yadira Guevara-Prip), who has been looking for the Spear of Destiny in order to get back to the Bad Place. To be fair, Sam and Dean did promise to get it back to her so she could return home and kinda fell through on the deal. The circumstances are especially dire now that Not-Kaia's home world is dying — at Chuck's hand, no less — and she needs their help to return. The only reason she knows this is because the real Kaia (Guevara-Prip) is still alive in the Bad Place, and they have shared visions, so she can see what's happening. This puts the Winchesters in a difficult position. In order to rescue Kaia, Jack wound need to use his powers to open the rift, which would then alert Chuck, who would then find and kill him all over again. Plus, it would go against Billie's strict rules, and the last thing they need is to piss off Death.

Cut to Cas and Jack at the bunker playing Connect Four, because this pure moment is exactly what we needed. When the Winchesters return, Cas jumps into stern dad mode to shoot down the idea of Jack's involvement in this risky plan. "Jack can't help her," he insists.

Jody, still fuming over being violently kidnapped, is also less inclined to help and appears more interested in throwing hands. Given what Kaia put her through, though, who could blame her?

Jensen Ackles, Kim Rhodes and Jared Padalecki, <em>Supernatural</em>Jensen Ackles, Kim Rhodes and Jared Padalecki, Supernatural

Jody is much kinder to Cas, who asks about Claire (Kathryn Newton). This tender moment marks the first time these two are meeting face to face. Jody reveals that she hasn't told Claire that Kaia is still alive, because she knows Claire would do anything to save Kaia, and if they fail, that would crush her. So for now, Claire will have to remain out of the loop.

Elsewhere, Jack tries to reach out to not-Kaia to apologize for not being able to help, and the evil doppelganger responds with major 'tude. After admitting that she only came to this Earth because she envied Kaia and wanted to see what it was like, only to learn that it's not the right place for her, she urges Jack to help her return to where she belongs. Moved by her plea, Jack uses his power to dreamwalk to Kaia in the Bad Place to gain a full sense of what's happening. What not-Kaia said was true, and he resolves to help. The reaper shows up just in time to object, threatening to rat him out to Billie. But Jack stands his ground and gives her two options: tell Billie that things went south under the reaper's watch or help them and Billie doesn't have to find out. Of course, the reaper opts for self-preservation.

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What the reaper neglected to reveal earlier was that she knows a way to restore the cosmic warding that Amara (Emily Swallow) stripped away from bunker walls, which might be enough to shield them from Chuck. It's a temporary solution to a permanent problem, but the Winchesters go for it. The plan might be risky — or, as the reaper puts it, "Winchester stupid" — but they're doing what's right, so it's worth it. Sam casts a spell to restore the runes, Jack opens the rift to the Bad Place, and the Winchesters are on their way to rescue Kaia.

Before Jody can join them, however, Cas stops her. He reminds the sheriff that if things go south and both she and Kaia die, that would utterly destroy Claire, so she should probably sit this one out. Cas will never be able to make it up to Claire for using her dad's body as his vessel, but he can at least try to keep Jody alive. His plea works, and Jody agrees to hang back while Sam, Dean and Kaia's evil doppelganger head off to the Bad Place.

They find themselves surrounded by red-eyed creatures who bear a striking resemblance to Star Wars' desert-dwelling humanoids, the Jawas. Terrified of their world ending, the creatures scurry away, and the gang is left to search for Kaia. It isn't long before they're face to face with the dreamwalker, who is very much alive and happy to see her friends. With the Bad Place crumbling, it's time to book it lest they be destroyed along with this strange alternate universe. At the last second, Kaia's doppelganger decides to stay behind and die with her world, which the Winchesters oblige.

At the bunker, the real Kaia greets Jody with a hug, and things suddenly feel right. After changing into Jack's spare clothes, Kaia reveals her method of survival to Jack: the nursery rhyme "Miss Mary Mack," which her mom used to sing to her. In a moment that we've been waiting for since Kaia was believed to have been killed, Jody invites her to come back to Sioux Falls, where she can finally be reunited with Claire. Hell yeah!

Lisa Berry, <em>Supernatural</em>Lisa Berry, Supernatural

Just when things are winding down, Billie pops in to kill her reaper for failing to do her one job and also to drop some very important knowledge on Team Free Will. She informs the gang that Chuck is wiping out all of the other worlds, save for theirs, as part of his twisted endgame. Sam, still worried about her plan, then confronts Billie about her ultimate game plan, and Billie finally spills the beans. When Cas killed her, she realized everyone can die — even God. It turns out Chuck has his own book in Death's library, which he cannot see unless Billie permits it. It's the result of him building himself into the framework of this world as a way of allowing it to sustain itself while he went off to create alternate universes. As a result, he architected his only weakness, and it's the Winchesters' destiny to stop him. As it is written, so it shall be: Sam and Dean are the messengers of God's destruction.

Back on Earth-2, Chuck, finally bored of chomping down on old takeout and watching his worlds die on multiple big-screen TVs, decides he's done with this world. He promises the poor sales guy who has served him for several weeks that everything will be fine, before walking out and promptly summoning an asteroid to destroy the planet. In case you weren't already aware, Chuck's a dick.

Supernatural airs Mondays at 8/7c on the CW.

Jared Padalecki and Jensen Ackles, <em>Supernatural</em>Jared Padalecki and Jensen Ackles, Supernatural