The BAU searches for an unsub in Austin, Texas who is targeting prominent members of the community.
The BAU hunts an UnSub in Maryland whose crimes are personal for Alvez, due to his time pursuing a Mexican hitman years ago. Alvez and Lisa move in together.
Jason and the SEAL Team have mixed feelings when they are tasked with bringing home an American soldier who was captured after deserting, in exchange for detainees in Gitmo.
Detective Slaughter returns to enlist Castle's help in solving a high-stakes robbery case. But when a body is found linked to the crime, Slaughter becomes the number one suspect in the heist turned murder, while Castle has to determine whether he's guilty or help to prove he's innocent.
After a van explodes during a Chicago street festival, a Muslim patrol officer Frank Toma (guest star Ben Youcef) goes missing and evidence quickly piles up pointing to his involvement. Burgess (Marina Squerciati) who helped train Toma is desperate to prove his innocence, even if that means going against her superiors.
