Karen McCann (Field) and her husband Mack (Harris) find their happy lives shattered when their 17-year-old daughter Julie is raped and murdered at home by deliveryman Robert Doob (Sutherland) while on the phone with her mother.
When Doob is released due to mishandled evidence, he starts making overtures to the McCanns' six-year-old daughter Megan while also intimidating Karen, who joins a vigilante group to defend herself.
Eye for an Eye provides examples of the following tropes:
- Asshole Victim: The movie is about a mother who hears her daughter raped and murdered by a grocery deliverer while talking to her on the cell phone, who gets off on a technicality, and decides to kill him.
- Bad People Abuse Animals: Robert Doob, an unapologetic rapist and murderer, is shown being mean to dogs.
- Forced to Watch: When Karen McCann is on the phone with her 17-year-old daughter Julie, she is forced to hear as Robert Doob rapes and murders her.
- Hollywood Law: The undercover agent who threatens Karen with life in prison if she kills Doob. In reality, Karen would probably get off completely or lightly, courtesy of an endless range of potential jurors — and even some law enforcement — who'd sympathize with her. Justified as the agent is attempting to intimidate her into giving up the idea and correctly states the punishment rather than practicality.
- Innocent Swearing: Robert teaches Megan the classic "Tough titty said the kitty, but the milk's still good" line, which she later repeats.
- Off on a Technicality: Karen seeks her own kind of justice on him after he gets off on a technicality. The tagline of the movie is "What do you do when justice fails?" In Real Life, at the very least, the killer's constant making faces at Karen would earn him a bunch of "contempt of court" charges.
- Outliving One's Offspring: This drama starts with Karen McCann talking with her home alone teenage daughter over the phone when the slime bucket Robert Doob breaks into the house and all Karen can do is listen as Doob rapes her daughter before killing her. Then the scum gets off scot-free and threatens her even younger daughter.
- Police Are Useless: Not only do they repeatedly fail via Off on a Technicality to stop Doob, but they even put more effort into stopping the vigilantes.
- Sean Connery Is About to Shoot You: Karen McCann is about to shoot you◊.
- Self-Defense Ruse: After a violent rapist is let Off on a Technicality, the Mama Bear of the young woman he raped and killed is approached by a group that teaches people how to commit vigilante executions and make them look like self-defense. The rest of the film revolves around the mother goading the man to come get her so she can commit said "self-defense".
- Vigilante Militia: Karen stumbles onto a conspiracy of Vigilante Men at a support group. They have very specific requirements: they only target killers whose guilt is obvious yet get Off on a Technicality, and they won't make the kill for someone else. Instead, they teach newcomers how to make the hit themselves. Something of a strawman case; the FBI has recognized a pattern of suspicious deaths among acquitted killers and has planted spies in support groups to track down the vigilantes. Karen discovers the spy in time to keep from incriminating herself seriously, but the agent still threatens Karen with life in prison despite being fully aware that the killer she's after has killed again. Ultimately, the FBI is powerless to protect the killer, as Karen pulls off the conspiracy's plan perfectly - make herself the killer's next target, then kill him in self-defense.
- Would Hurt a Child: After raping and murdering Julie, Doob begins making overtures at Karen's six-year-old daughter Megan.