In the series finale, Moretti goes missing on the day of her wedding, and Pierce soon discovers that she's been abducted by a dangerous person from his past.
Pierce attempts to find the killer of a student while defending the victim's boyfriend, who is believed to be mentally ill and guilty of the crime. Pierce has to face up to his feelings about Kate as her wedding day nears.
Pierce and Moretti stumble on an international scandal when investigating the murders of a Bangladeshi diplomat and a Chicago reporter. Kate struggles as she prepares for her wedding so she asks Pierce for help.
Moretti goes undercover to investigate the brutal murders of meat-company owners. Meanwhile, Pierce contemplates making a personal confession to Moretti.
Daniel's father and his friend Dean Haley are faced with the decision on whether to allow Pierce to undergo a high-risk surgery for his traumatic injury. Daniel works on solving a different kind of murder case.
Pierce helps Donnie when Donnie finds himself in a compromising situation and evidence stacks up against him. Meanwhile, Pierce's father assaults someone at an assisted-living facility.
A sniper targets the Federal Building lobby, putting Moretti and Donnie in the crosshairs. Before long, Pierce concludes that the shooter fears low-frequency radio waves. Meanwhile, a beguiling woman prompts Donnie to run for office.
A missing FBI agent is found dead in an investigation that forces Pierce to face a past unsolved case, and Pierce's therapist grows concerned that the investigation may exacerbate Pierce's condition.
Pierce witnesses the death of a gallery owner, but he comes to believe it was actually a murder. Pierce and Moretti try to hunt down the killer, only to end up in the middle of a daring art heist. Meanwhile, Pierce analyzes his relationship with Natalie.
An infant is reported stolen. Moretti tracks the kidnapper, only to make a bizarre discovery. Elsewhere, Pierce and Moretti probe a related murder, and Donnie sets out to buy a house in the suburbs.
A notable neuroscientist is found dead, and Pierce and Moretti must determine how the killer infiltrated the victim's impenetrable study to commit the deadly deed. Meanwhile, Pierce's father moves in with Pierce and Lewicki.
Pierce examines a woman who has confessed to a murder and claims to be possessed by the devil. Meanwhile, obstacles mar Donnie and Moretti's wedding plans.
A boy with a developmental disorder is taken hostage during a bank robbery. Elsewhere, Pierce's estranged father visits.
A prosecutor mysteriously drops dead in the courtroom, trigging an investigation by Pierce and Moretti. Meanwhile, Moretti and Donnie make important life decisions.
Season 3 opens with Pierce's new life in Paris upended when he's enlisted to probe a risky international case. Elsewhere, Max and Dean Paul Haley scheme to bring Pierce back to Chicago.