When Benson and Stabler investigate a series of assaults in the Upper West side, they find that they will have to rely on the help of psychiatrist Rebecca Hendrix and her schizophrenic patient, also a victim of this crime, to nail down their predator. The investigation takes an unexpected turn when Benson and Stabler locate the criminal, Thomas Mathers. However, conflicting evidence leaves Benson and Stabler questioning whether or not Thomas is the right man to have in custody.