The Adult Swim cartoon-for-grownups Rick and Morty returns for a second season on Sunday to continue celebrating the bad behavior of an alcoholic mad scientist (Rick) and his teenage grandson (Morty)—and season two promises to be even more insane than the first. We’ve put together a primer for the uninitiated.

What can viewers expect from season two?In an interview with the A.V. Club, Harmon, Roiland, and writer-performer Ryan Ridley threw out a few hints about the new season. Of particular note is a guest appearance by Stephen Colbert, who’ll voice a character that’s as brilliant as Rick, which drives Rick crazy. Fans can also expect the already massive character universe to grow; one episode alone has more characters than all of the first season. Any fans worried that the show’s creative impulses have been tamed shouldn’t worry—the season two premiere plays out in two horizontal panels, with slight variations in the action that lead to wildly different outcomes for the characters.