How Rick and Morty season 6 will balance canonical lore and one-off adventures

Over its first five seasons, Rick and Morty has built up a fascinating mythology for itself — but only rarely does the popular animated sci-fi comedy clue viewers in to the secrets of its canon. Most Rick and Morty episodes are standalone adventures featuring characters or settings that rarely reappear. But every five or six episodes, viewers get treated to a deeper dive into bigger threats, the backstory of super-scientist Rick Sanchez (Justin Roiland), and other bits of canonical lore.

The latest such episode was the season 5 finale, which finally brought the long-simmering Evil Morty plotline to a new level and permanently changed the fabric of the show's universe. As a result, the Rick and Morty season 6 premiere (airing Sunday on Adult Swim) will pick up where the finale left off, showing how Rick and his grandson Morty (also voiced by Roiland) navigate their changed world with the help of some familiar faces.

"We had a lot of loose threads that we needed to answer," showrunner Scott Marder tells EW. "So it was important to us to give a big first episode back that really delivered on what the finale from season 5 had left open. We wanted to do that, but then get us to what we're good at doing, which are episodes like [season 6, episode 2] and onward that are great standalone ones. For me, season 6 is a nice step up on season 5 in that it's got great episodes, but it's also got a little bit more continuity and self-awareness and a little bit more interconnectivity than the previous one, as well as a balance between canon and non-canon."

Summer (Spencer Grammer), Rick (Justin Roiland), and Morty (also Roiland) on season 6 of 'Rick and Morty'
Summer (Spencer Grammer), Rick (Justin Roiland), and Morty (also Roiland) on season 6 of 'Rick and Morty'

Adult Swim Summer (Spencer Grammer), Rick (Justin Roiland), and Morty (also Roiland) on season 6 of 'Rick and Morty'

Rick and Morty co-creator Dan Harmon admits that he doesn't always think to build on the show's canon, and prefers the standalone stories. But since the show launched in 2013, cadres of younger writers have gotten involved with a passionate interest in exploring that mythology.

"My wisdom needs to replace my tyranny," Harmon says. "I'm not like a 35-year-old writer anymore whose biggest contribution is all this intensity about what can and can't happen. I need to be more like, 'Oh, you're intense. Let's listen to what you're intense about and, since I have broken a thousand stories, let me help you figure out the difference between a satisfying story and an unsatisfying one."

Marder adds that there's no "hard-and-fast rule" for how the creative team decides when to do a world-building episode and when to do a fun adventure.

The season 6 premiere "presented a really cool sci-fi conceit that organically let us look backwards and forwards," Marder says. "[The episode] is another awesome sci-fi concept that would've stood on its own, but also became a cool way to pay tribute to one of my favorite things that I had ever seen on this show."

Rick and Morty season 6 premieres Sunday, Sept. 4, at 11 p.m. ET/PT on Adult Swim.