Heather Ratner née Chandler, worked for an organization later known as Volkoff Industries and is the former captain of the high school cheer leading squad, bully and tormentor and nemesis of Sarah Walker (when the latter was using the alias Jenny Burton) and subsequently married their classmate Mark Ratner.
Through out the episode we see flashbacks of Heather, then a cheerleader, picking on and taunting Jenny Burton, about the fact that her dad had been arrested and was in jail. She also teased her about her dreams of being an actress; years later, Heather remarks that if she had known that Sarah had joined up with the CIA, she would've made the same tease still.
It is revealed that after encouraging her husband to go into weapons design, she orchestrated a false protection racket whereby her husband was convinced to trade secrets regarding an advanced combat aircraft for the United States Air Force to the Russian mob in exchange for her safety.
With the failure to get her husband to do his part, she has ruined a $500 million deal Volkoff was holding for the F-22 bombers that Mark Ratner had been working on during "Chuck Versus the Cougars", which led to Volkoff assigning Hugo Panzer to assassinate her in "Chuck Versus the Cubic Z".
When Heather recognizes Sarah at the Buy More, Sarah's cover identity is in danger and Sarah must face her fears when she is given the job of spying on Heather at 10-year high school reunion after Heather's character also shows up. She and Sarah engage in a martial arts catfight at their ten-year high school reunion in San Diego. Sarah was able to knock her unconscious by hitting a cougar statue with one of her knives, which fell and hit Heather on the head.
Heather is later revealed to work for Volkoff. She returns, with "Stone Cold" Steve Austin as Hugo Panzer, in "Chuck Versus the Cubic Z". At some point when being interrogated by Sarah and Chuck, she intuitively realizes that Chuck and Sarah were actually dating. She begins to needle Sarah on her choice and even manages to anger Sarah more and more.
She warns Chuck that spies are purely deceptive, and that Sarah's feelings for him aren't real. When Volkoff's agents turn up at the Buy More to capture Heather, she urges Sarah to give her up, it's what she would do. Sarah retorts that they're not the same. Together, they gun down Volkoff's agents before Heather surrenders. She later tells Team Bartowski that she had once worked with Frost on Operation Beacon. She is then returned to custody.
The character name is an homage to the cult film Heathers.