John Lithgow won an Emmy for his performance as Arthur Mitchell, a.k.a. the Trinity Killer, in the fourth season of the Showtime television series Dexter. That was twelve years ago, but now that Dexter is being brought back for a ninth season (the first eight seasons can be purchased at THIS LINK), the Trinity Killer is somehow coming back as well.
Lithgow has signed on to make a "short but decisive" appearance as the Trinity Killer in the new season of Dexter. According to Deadline, the writers have found a way for him to return that "works within the larger Dexter narrative". Lithgow is only expected to be on set for "a day or so".
The revival season will consist of ten episodes and has the following synopsis:
Set 10 years after Dexter Morgan went missing in the eye of Hurricane Laura, the revival sees the character now living under an assumed name in a world away from Miami.
Lithgow joins a cast that includes Michael C. Hall as Dexter, Clancy Brown as Kurt Caldwell, the primary villain and "the unofficial mayor of the small town of Iron Lake, New York". Caldwell's a former truck driver who now owns several trucks and the local truck stop; Jamie Chung as Molly, "a famous true-crime podcaster from Los Angeles"; Julia Jones as Angela Bishop, "the first Native American Chief of Police in her town in upstate New York"; Johnny Sequoyah as Audrey, "Bishop's brash and opinionated teenage daughter"; Alano Miller as Logan, "a sergeant for the Iron Lake Police Department and the assistant wrestling coach for the local high school"; Michael Cyril Creighton as Fred Jr., "the congenial owner of Fred's Fish & Game"; Oscar Wahlberg, as Zach, "the captain of the Iron Lake High School wrestling team"; and Jack Alcott as Randall, "with whom Dexter has a meaningful encounter".
Hall is executive producing this new batch of Dexter episodes alongside showrunner Clyde Phillips, John Goldwyn, Sara Colleton, Bill Carraro, Scott Reynolds, and Marcos Siega, who will be directing six of the episodes. Siega previously directed nine episodes of Dexter over the course of its second, third, and fourth seasons.
It should be noted that Phillips also served as showrunner on the first four seasons of Dexter's original run, meaning his run on the show ended at the same time Lithgow's did. It seems he felt there was a little bit of unfinished business there.