Six months after the events of “Ricksy Business”, Rick, Morty, and Summer unfreeze time, but because the three of them were displaced from time for months, the kids’ uncertainty about their relationship with Rick causes time to break, splitting into two separate timelines in a decaying, Schrödinger’s cat-filled dimension, that both does and does not exist. Meanwhile, Beth and Jerry go out for ice cream and end up hitting a deer. Jerry questions Beth’s ability to save it, so they make their way to an animal hospital. Upon arriving it is revealed that the deer was shot by a hunter, just prior to being hit by the car, and the hunter is claiming it for his own. Beth is able to save the deer’s life and release him, to the delight of a nearby Native American. Rick manages to sync his grandchildren with their counterparts, but he loses his sync when he attempts to remerge the timelines, causing another fracture that attracts the notice of an all-powerful, fourth-dimensional being. The being makes collars for the trio that re-merges the humans’ timelines, but then attempts to arrest them as Rick’s device was powered by a stolen crystal. Rick, Morty, and Summer break their collars, and use uncertainty to break time further, allowing Rick to beat up the being simultaneously across multiple timelines. Morty’s collar’s latch is broken so Rick sacrifices himself, and gives Morty his collar, as the dimension they are in is crumbling around them. Rick is in the process of accepting his fate, when he manages to find and fix Morty’s collar, at the last second.
Post-Credit Scene: The being and his friend beat up Albert Einstein (whom they mistook for Rick) for messing with time. After they leave, Einstein swears revenge on the two beings and comes up with formula E=mc².