The squad jumps into action when the victims of an apparent serial killer begin turning up throughout the region. Ham is temporarily partnered with Butch while Bobby is on an undercover assignment. And Grace is paired with Abby Charles (special guest star Christina Ricci), a uniform cop and single mother making a rotation through the squad. Meanwhile, as Leon Cooley's execution date rapidly approaches, Earl tries to persuade Grace to find someway to help him before it's too late.