She was played by Gina Holden.
Six years prior to the film's events, Heather Ward met her future husband, Cam Ward, and engaged in a one night stand with him. Cam later began a relationship with Marissa Davis (the film's protagonist), and proposed to her after learning that she was pregnant with their baby. In a jealous rage, Heather ran down Marissa late one night while both women were in their vehicles. Marissa was placed in a coma for six years, and gave birth to her daughter, named Abby, while she was incapacitated. With Marissa out of the way, Heather married Cam, and they raised Abby together.
Marissa was revived from her coma after six years, and Heather was one of the first people she encountered. Heather, knowing Marissa's memory was fuzzy, posed as her best friend, leaving Marissa unaware of her true villainous nature, and informed Marissa that Cam is now running for Senator. When Marissa was learning the truth about Abby, piece by piece, Heather attempted to convince Marissa's mother, and others, that Marissa is mentally unstable. Meanwhile, Abby needed a kidney transplant, and at that moment, the evil Heather decided to use this opportunity to attempt to kill Marissa. She had her henchman (and suggested lover), Peter Vaughn, kidnap Marissa and hospitalize her, so the procedure can be performed and they could kill Marissa, making it look like she died during surgery. During a confrontation, Heather reveals her evil plan to Marissa, who figures out that Heather was behind the hit and run that put her in a coma. After the confrontation, Heather informs Peter to make sure Marissa actually dies this time.
After Marissa escapes with Abby, she is chased by Heather and Peter, with the latter holding Marissa at gunpoint. After Cam sees what's going on and learns the truth about his wife, Heather grabs the gun with the intent on killing Marissa herself, only for Marissa to fight Heather and grab the gun herself. Marissa lowers the gun when she sees snipers hovering over her, but when Heather attempts to attack Marissa with a box-cutter, Marissa shoots her. Heather is last shown carried on a stretcher and being placed in an ambulance.