With Michael C. Hall returning as Dexter Morgan's inner voice, Patrick Gibson steps into the serial killer's shoes for the prequel series -- set in 1991 Miami. The show will show him transition from student to killer, with Christian Slater starring as Harry. The series also stars Sarah Michelle Gellar, Patrick Dempsey, Christina Milian and more -- some playing younger versions of roles from the original show. Dexter: Original Sin premieres Friday, December 13 on Paramount+ with Showtime.