A young FBI agent, Rebecca Locke, is brought onto the Los Angeles Violent Crimes Unit to track down the serial killer who murdered the agent she's replacing. She immediately shows her prowess by discovering that the agent had staged her suicide to look like a murder. The leader of the team, Virgil Webster, chose Rebecca because of an incident in her past when she was abducted.
The team investigates a series of murders that seem to revolve around a S&M club. Rebecca gets close to an initial suspect, a S&M practitioner, but the real suspect turns out to be the cop who initially investigated that man for a rape charge and subsequently became fixated on him.
The team tracks a Pre-Filer, a man who hunts down would-be serial killers before they act. He eventually takes Rebecca hostage and tries to make a believer out of her.
The murder of an 8-year-old in a private, gated community prompts Web to play each of the team members against one another.
Rebecca goes undercover to track a serial killer targeting suicide hotline callers. Meanwhile, Paul has concerns about Web's growing influence over Rebecca.
When a serial killer copies the murder of a man imprisoned for cutting out women's hearts, Paul is taken back to the familiar ground of his very first case on the job.
An agent with an ax to grind against Web is brought in to lead the team while Web is being investigated, as the team tracks down a killer with a love of stun guns and a habit of removing its victims' fingernails.