Psych duo preview Shawn and Gus' growing pains in Lassie Come Home

Almost three years after Psych: The Movie, fake psychic detectives Shawn (James Roday Rodriguez) and Gus (Dulé Hill) are back in a sequel that marks a return to basics for the zany USA Network drama, which ended in 2014.

"We wrote a pretty big movie the first time around," says Rodriguez, who co-wrote Peacock's Psych 2: Lassie Come Home with Psych creator Steve Franks and longtime series scribe Andy Berman. "[The sequel] was basically a trip back in time to the spirit of this show in the middle of its run, as opposed to trying to make everything bigger, badder, faster."

Picking up in real time after the last film, Lassie Come Home finds Shawn and Det. Juliet O'Hara (Maggie Lawson) navigating married life as Gus adjusts to being in a long-term relationship with Selene (Jazmyn Simon). "It's really about [them] trying to balance those two things of trying to be grown up but still having this tug of being Toys 'R' Us kids," says Hill. "Things happen in life where they have to grow up and start to mature, but they still want to maintain a semblance of who they are in terms of their relationship and what they like to do. So, that's something that I think most people can relate to because that's just what life is. Life evolves, and life grows, but you still don't want to completely lose that childlike side of you."

When their friend, Chief Carlton Lassiter (Timothy Omundson), is gravely injured in the field, the duo head home to the sunny "murder capital of the world," a.k.a. Santa Barbara, to investigate his expensive and haunted rehab facility. Omundson didn't have a significant role in the first reunion due to a stroke he suffered right before production, and Psych 2, which wrapped over a year ago, was his first post-recovery project.

"The one thing we knew we absolutely wanted to do was structure a story around Lassiter so Tim could come back," says Rodriguez. "Then, it was just about figuring out what [Omundson's] limitations might be, what he was comfortable doing, how much we could use him, [and] then kind of reverse engineering those elements into a story that made sense because the whole point of the movie from our perspective was bringing Lassiter back for the fans and getting Tim back on the horse."

Having Omundson back on set ended up being a very intense experience for everyone involved. "We managed to bring back I would say about 80 percent of our original crew [from the show]. Everybody was there for the first time thatTim set foot back on a set. It was really beautiful because we were a family and it was absolutely the right way for him to do it and he could not have had more support and love behind him," Rodriguez recalls.

Adds Hill: "It was just so moving just seeing him back in Vancouver, back on set...You can't have Psych without Lassie."

2017's Psych: The Movie setup some expectations for the sequel because it ended with Shawn and Gus fleeing the Psychfrancisco offices with Juliet's spy brother Ewan (John Cena) as bullets rained down; however, Lassie Come Home doesn't tie into that final scene because it was built around Lassie's return.

"As not to create expectations that don't get met there is no Ewan O'Hara in [Psych 2]," says Rodriguez. "I do think it would be very possible to revisit what happened from [that moment] in the future and it would be a lot of fun and I know Cena would be into it. There is a reference to something that sort of gives you an idea of where that might have gone, but for the purposes of the second movie we do not pick it up from the end of the first."

Psych 2: Lassie Come Home hits Peacock on Wednesday.

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