- "I know what it's like to see ghosts that don't go away. To be watching a scary movie in your head, whether you want to or not, watching it alone. "
- —Kancaid to Sidney.
He is next seen with his partner, Detective Joshua Wallace, at the studio set of Stab 3. However, he and Wallace are only seen briefly and Mark doesn't even have a line in the scene. The scene shows them exiting the studio lot, when they are asked by one of the executive managers whether Cotton's death may have been inspired by his involvement in Stab 3. His partner replies: "He was making a movie called Stab. He was stabbed."
His next appearance shows Wallace present as well, where he is at the official crime scene of another Stab 3 cast member, Sarah Darling. He informs Gale that whoever the killer is, he's killing his victims in order of how their characters die in the script for the film, Stab 3. However, there were about three different rewrites and they don't have any clue which one the killer has read.He questions Roman Bridger, the director of the movie, about the death of Sarah and accuses him of calling her before Sarah's death, although Roman didn't say anything about calling her. Distraught, he and his partner take him down to the station for further questioning. They let him go when they discover that his cellular phone record is clean.
After the murders of Jennifer Jolie 's bodyguard, Steven Stone, and another Stab 3 actor, Tom Prinze, Mark investigates the discovery of another photo of Maureen Prescott from nearly thirty years ago, only with this one suggesting the Ghostface responsible for the Stab 3 murders was also involved in the murder of the first Ghostface victim, Maureen.
While at the station, Sidney goes to see her old friend Deputy Dewey Riley and meets Mark for the first time. Sidney tells Mark about the fact that the killer called her. He shows her the photographs of her mother that the killer leaves behind after every murder. She asks him what he "knows about trilogies". He explains his knowledge of movie trilogies, leaving Sidney unsure if she can trust him or not.
During the final act, Mark follows Sidney to John Milton's mansion, where he quickly becomes aware of the kidnappings of Gale and Dewey and the murders of three more Stab 3 cast members, Angelina Tyler, Tyson Fox and Jennifer Jolie. He arrives just as the killer flees, rendering Sidney suspicious of Mark. But then, the real killer appears from behind Sidney. Mark manages to push her out of the way of the knife and, as a result, is stabbed in the chest and brutally wounded. He later hands Gale and Dewey one of his guns after they are freed. He places his other gun in his hand and navigates the area before finding Sidney and a recently murdered John Milton in a hidden theatre room where he is knocked unconscious by a surprise attack from the killer. He ultimately survives his injuries with assistance from the other remaining survivors. In the epilogue, Mark can be seen in Sidney's home, putting on an unspecified horror movie to watch with her, Gale, and Dewey.
Behind the Scenes
- He was described as "mid-thirties. Handsome with piercing eyes" in the script.
- Dempsey was offered to reprise his role as Det. Kincaid in Scream 4, but he denied due to his commitment to Transformers: The Dark of the Moon. Kincaid's character was then written out of the script.
- The writers also, were going to expand on the relationship between Mark and Sidney if they brought him back for Scream 4, (example, they would be in a relationship together). However, since Patrick Dempsey didn't reprise his role as Mark, the relationship didn't go any further, and Sidney was single in Scream 4.
- Patrick Dempsey would later star in TV series Grey's Anatomy, which featured his Scream 3 co-star Neve Campbell in a two-episode supporting role as his character's sister.