Knowing that her father's business was failing, and in an effort to prove herself to her father, Ashley decided to drill on a oil rig that was actually located on a fault line. She killed safety inspector Butch Hicks, who warned her of risks and attempted to stop her operation, and she also killed Christopher Renard, a geologist hired by Ashley, who also sent anonymous tips threatening to go to the authorities. Regarding Hicks' death, Ashley tampered with a crane, causing it to go loose and kill Hicks.
Ashley was revealed as the villainess when she encountered Shawn and Gus in Renard's office, where they were inspecting the maps of the rig. The pair originally thought that Billy Joe was the culprit, but at that moment, Ashley turned heel and pointed a gun at Shawn and Gus and locked them in a small room full of toxic materials. Later on, the evil Ashley encountered Chief Vick, along with Jules, Lassiter, and Coast Guard commander (and Vick's sister) Barbara Dunlap, where they learn that she was on the rig the night that Hicks was killed. When they see Ashley's gun, the cops charge at her, which led to a gunfight. After Shawn and Gus are freed, Shawn attempts to calm Ashley down, stating that he can sympathize with having an unappreciative father, and she did what she felt she had to do to save her father's business. Ashley lets her guard down, allowing Lassiter to subdue and arrest her.
- Kelly Overton also appeared as the evil Lynette Richmont on CSI: NY, and later played recurring villainess Claire Sinclair on The CW's Beauty and the Beast.
- "You shouldn't have come back out here, Shawn. Now I'm going to have to figure out a way to get rid of you." (Ashley's villainous reveal, while pointing a gun at Shawn and Gus)