You're probably confused because there are a TON of King-based adaptations coming to film and TV this year between the Dark Tower, Castle Rock, It, and more—so here's a primer for you.
Mr. Mercedes is coming from TV veterans David E. Kelley (Ally McBeal) and Jack Bender (Lost), who are writing and directing the pilot respectively. Though there isn't an exact date set for the first episode, we now have our first look at the show courtesy of its Facebook Page.
The only image of an actor features Harry Treadaway, formerly of Penny Dreadful, as Brady Hartsfield. The other are stills from the production meant to add to the creepy atmosphere the show will mine.
Hartsfield was originally supposed to be played by the late Anton Yelchin who unfortunately passed in 2016.
Based on Stephen King's 2014 book, Mr. Mercedes follows demented killer Brady Hartsfield (Treadaway), who taunts a retired police detective Bill Hodges (Gleeson) with a series of lurid letters and emails, forcing the ex-cop to undertake a private, and potentially felonious, crusade to bring the killer to justice before he is able to strike again.
Brendan Gleeson leads as Detective Bill Hodges, along with Harry Treadaway (Penny Dreadful) as Brady Hartsfield. Jharrel Jerome (Moonlight) is cast as Jerome Robinson, Scott Lawrence (Avatar) as Detective Peter Dixon, Robert Stanton (Mercury Rising) as Anthony "Robi" Frobisher, and Ann Cusack (Nightcrawler) as Olivia Trelawney, with Mary Louise-Parker (Weeds) as Janey Patterson, and Holland Taylor (The Truman Show) as Ida Silver. Kelly Lynch (Deborah Hartsfield), Justine Lupe (Holly Gibney) and Breeda Wool (Lou Linklatter) also star.