Rick and Morty has made it clear that the show will shy away from continuity-heavy storylines, but one plot point seems to be coming back around in Season 5. The new season trailer shows that Morty's long-time crush, Jessica, will play a big role. She makes at least two appearances, including one sci-fi moment and one (relatively) quiet family moment.
Jessica — voiced by Kari Wahlgren — was introduced in Rick and Morty's pilot episode as Morty's mysterious school crush. She has made sporadic appearances, often seeming to like Morty without taking a particular interest in him. She has only gotten tangentially involved in the titular characters' sci-fi hijinks, but that might change this year, judging by the trailer. She first appears at the 18-second mark, standing with Rick and Morty in some kind of cube, surrounded by dog-like robots and looking fearful.
"What are they mad at you for, anyway?" Morty asks. Rick responds: "Well, we're talking about me — it could be anything."
Jessica next appears at the 1-minute, 15-second mark in the trailer, coming around the corner into the Smith family kitchen just as some kind of humanoid alien in a green spacesuit attacks Morty. Beth and Jerry watch in pajamas, indicating that Jessica is present for some private family moments this year.
What Jessica could be doing on a Rick and Morty adventure is a mystery, but what she's doing in the Smith family house at twilight is equally intriguing. The show has often played with fans' expectations of Morty "getting the girl" before, bringing him extremely close to telling Jessica his true feelings before resetting the timeline with some convenient plot device.
Of course, altering Morty's relationship with Jessica in any real, long-term way might be out of the question of the show that spent much of Season 4 telling fans that it would not do continuity-heavy plotlines going forward. The show has not touched its fan-favorite "Evil Morty" cliffhanger from Season 3, and it dedicated a whole clip-show episode, "Never Ricking Morty," to deconstructing its own "potential" for call-backs and recurring bits.
However, Rick and Morty have allowed subtle shifts in their characters' relationships to inform the stories from season to season. This includes Beth and Jerry's separation in Season 3, Beth's reckoning with Rick's parenting issues and Morty's slow metamorphosis from fearing Rick to admiring him and then to distrusting him in general. Whether Jessica is eligible for this kind of storytelling is up to the writers.