She was played by Michelle Nolden.
Laura Stevens is a physical trainer and a hypnotherapist, but her sinister past revealed that she attempted to kill her stepfather. Laura claimed that it was because he was abusing her mother, but in actuality, he knew that she was mentally unstable and wanted to commit her. It was also revealed that she killed her mentor, Charles McDowell, after she made repeated attempts to contact him. Laura took on Delphine, a noted athlete, under her wing, but after she became increasingly controlling, Delphine fired Laura. An angry Laura later killed Delphine by drowning her.
In the film, Alison Wynn (the film's protagonist) became Laura's latest client after being sideswiped while running. Alison met Laura at a seminar and quickly agreed to hire Laura as her trainer, despite Laura's warnings about her strenuous methods. Unbeknownst to Alison, Laura set her evil plan in motion, which was to separate Alison from her family, beginning with taking Adam, Alison's husband, out of the picture. After noticing how the family's young blonde neighbor acts flirtatious with Adam, Laura planted a pair of women's underwear inside the home on the couch to make Alison believe that they're having an affair, which works. Laura continued the ruse when Adam called wanting to talk to Alison, making it appear that Adam was threatening her. Later on, Laura spiked Alison's wine, leading to Alison quickly knocked out due to the effects. She later confronted a reporter who had been looking for answers regarding Delphine's death, and after he reminded her about her dark past, the evil Laura snapped his neck, killing him.
Laura later encounters Adam and warns him to divorce Alison or she will ruin his life. When he turns her down, Laura smases a bottle on her own head and makes it appear that Adam attacked her. By the film's climax, Laura's motive becomes clear. She is in love with Alison; this is confirmed when she makes out with Alison. After Kayla, Alison's daughter, tells Alison that she saw Laura at the house unannounced, a confrontation ensues between Laura and Alison, which leads to Laura attacking Alison, while revealing to her that she killed Delphine. She later attempts to kill Adam as well, but Alison gets to Laura in time. The women tussled in the pool, with the fight ending with Laura drowning.