The premiere picks up shortly after the season 5 finale, with the Citadel destroyed and Rick and Morty drifting in space. After a great “Avengers: Endgame” parody, the duo is rescued by space clone Beth and brought back to Earth, where Rick resets the multidimensional fluid required to repair his broken portal gun. The problem is that this resets every interdimensional traveler in this dimension. This applies to Rick — who we know is from a dimension where he lost his wife and his daughter — and Morty — who hails from a dimension where every human turned into a Cronenberg monster after Morty’s love potion got out of control. But Jerry also arrives glowing green just like Rick and Morty. Why? Because of the Jerryboree of course!
The Jerryboree made its debut in the season 2 episode “Mortynight Run,” the episode that introduced audiences to the Blips and Chitz arcade and the game “Roy: A Life Well Lived” and followed Morty’s adventure befriending an alien assassin that bought guns from Rick. But before they could finish the shady deal, Rick and Morty have to deal with a stowaway Jerry. Their solution? Leave him at a daycare. And at some point, a Rick decided it would be useful to leave his Jerry at a safe place, so a daycare at a Furp Rock Plaza on an unregistered cross-temporal asteroid was opened. There are dozens of Jerrys at any time, and they have miniature models, a ball pit, a TV with customizable settings for the Jerrys to play with, and an employee in a big Beth costume serving as a mascot.
At the end of “Mortynight Run,” Rick and Morty return to Jerryboree to pick up Jerry, but Morty accidentally crashed into another Morty and both their ticket stubs fall to the ground. This forces Rick to simply pick a Jerry at random. It was a silly, funny end to the story, not really meant to be a mystery, let alone a story with any serious repercussions. Until now.