The full story
With Thor gone, Darryl Jacobson takes a job in Los Angeles and advertises for a new housemate. The only reply comes from the Grandmaster, last seen on Sakaar at the end of Thor: Ragnarok.
The Grandmaster treats Darryl as his new assistant: taking out the trash, driving him around, never quite respecting his personal space. He has decided to rule Earth, with Darryl at his side, and posts a video announcing it. It gets no views, so he plans a second video with a musical guest, hires Darryl's friends to help, and melts one of them when they don't live up to his expectations. Darryl admits he isn't sure he won't be next, and that he misses Thor.