Derek Walker is an adrenaline junkie who likes to take part in extreme sports together with his friends Jessica Martino (also an ex-girlfriend), Stuart Crawford and Ruby Jay. He used to be a big-game hunter, but he turned over another leaf after bagging the African Big 5.
However, this change of heart seems short-lived. When Stu's company goes bankrupt thanks to his business partner Brian Sampson's extravagancies, Derek promises Stu that he will kill Brian and let Stu collect his life insurance. He uses his key to Jessica's apartment to retrieve the Winchester 70 he had given her after giving up hunting and commits the murder. Having gotten cold feet in the meantime, Stu freaks out upon hearing the news and plans to disappear, executing the escape while river rafting with the group. As Derek can't have Stu going to the authorities, he tracks him down by GPS to his hide-out in Lone Pine, CA and commits his second murder. After making it look as if Stu committed suicide after supposedly killing Brian, Derek thinks he is out of the woods.
When the SBPD find the body, Derek goes paragliding with Ruby to help her deal with Stu's death. However, Ruby looks at Derek's GPS as they are about to take off and notices that Lone Pine is in it. His gruesome secret discovered, he explains the pact to her and says that murder is the best adrenaline rush he has ever felt, "like lightning running down your spine". He proceeds towards her menacingly and almost walks her off the cliff, but Shawn, Gus and the police arrive just in time to save her. Derek tries to make a break for it by paraglider, but Gus jumps on him and brings him to the ground by squeezing him so hard (out of fear) that he loses consciousness, after which the police bring him in.
Trivia[]
- He met Stu at a wildlife preservation meeting.
- He twice took Jessica to Africa with him while they were dating.
- He tells Shawn that he and Jessica would make a great couple.