After a young victim with a developmental disorder is taken hostage in a bank robbery, Moretti brings in Pierce to interview the boy. When they finally track down the culprits, they discover the case is about much more than money. Meanwhile, Pierce's estranged father James pays him a visit.
When renowned Neuroscientist Landon Jennings is found dead, Moretti and Pierce must figure out how someone could have gained access to his impenetrable study in order to kill him. Lewicki finds himself with twice the work when Pierce's father James moves in with them.
When an infant is reported stolen, Moretti hunts down the kidnapper and makes a very bizarre discovery. As Pierce and Moretti investigate a related murder, they find that there might be another child out there who needs their help. Meanwhile, Donnie and Moretti discuss their future together when Donnie looks into buying a house in the suburbs.
Donnie wakes up next to dead Shelby, calls Pierce to help him. Pierce and Moretti tries to clear his name. Pierce's father gets mistaken as Ruby's husband. He asks him and Moretti to find her actual husband (a wanted gangster).
After Dr. Daniel Pierce suffers a traumatic injury, his father and his friend must decide if they should allow him to undergo a high-risk surgery; Pierce begins to question everything he sees and hears.
After a student is found murdered, Pierce tries to find the killer while defending the victim's boyfriend, who is believed to be mentally ill and guilty of the crime. Meanwhile, Pierce must confront his feelings as Kate and Donnie prepare for their wedding day.