Sarah Michelle Gellar has joined Paramount+ with Showtime’s prequel series Dexter: Original Sin. The actress will play Tanya Martin, the CSI Chief at the Miami Metro Police Department and Dexter’s new boss. Dexter: Original Sin is set in 1991 Miami, 15 years before the original series, as Dexter “transitions from student to avenging serial killer.” “When his bloodthirsty urges can’t be ignored any longer, Dexter must learn to channel his inner darkness. With the guidance of his father, Harry, he adopts a Code designed to help him find and kill people who deserve to be eliminated from society without getting on law enforcements’ radar. This is a particular challenge for young Dexter as he begins a forensics internship at the Miami Metro Police Department.” Christian Slater and Patrick Dempsey also star in the series.