Thirty-two-year-old Ronnie Molland is a savvy, competent detective-so when she receives a stack of murder cases, each linked by a mysterious symbol at the crime scene, she wastes no time trying to find what each victim has in common.

Soon she discovers that the targets are anything but random. Rather, each victim had been abusive toward animals-with each murdered in the same manner that they killed an animal.

Unbeknownst to Ronnie, an animal rights activist named Madame Lee operates a secret facility in an old mine designed to punish animal abusers. Convinced in the righteousness of her cause, all Madame Lee needs is an ally on the police force to ensure that she can continue bringing her vigilante justice to the disgusting humans who commit atrocities against animals. When Ronnie's dog is brutally murdered and his attacker goes free, Madame Lee sees the opportunity she's been waiting for to get an officer of the law on her side.

The more she learns about Madame Lee's operation, especially in the wake of her own tragedy, the more Ronnie comes to sympathize with the vigilante group. But is fighting violence with violence really the more humane path to justice?