Moretti calls on Pierce to examine Elena Douglas, a woman who has confessed to murder and claims to be possessed by the Devil. Meanwhile, Donnie and Moretti’s wedding plans hit a bump in the road.

Pierce and Moretti uncover an international scandal while investigating the murders of a Bangladeshi diplomat and a Chicago reporter; Moretti struggles with the preparations for her upcoming wedding.

When a student is found murdered, Pierce tries to find the killer while defending the victim's boyfriend; Pierce must confront his feelings as Kate and Donnie prepare for their wedding day.

When Moretti goes missing the day of her wedding, Pierce and Donnie set off in pursuit of the runaway bride. They soon learn that Kate has been abducted by a dangerous person from Pierce's own past. Now, Pierce and Donnie must risk everything to save Moretti before it's too late.