Suspecting that Kate's niece and her friend have been taken by an online predator, the team's hunt takes on a particular urgency as they try to find the pair before they get hurt.

In the wake of a series of fatal shootings, the BAU team travel to Illinois to investigate what appears to be a copycat serial killer.

Erin is conflicted by the weight of her authority in the sentencing of a man guilty of vehicular homicide; Danny and Baez pursue a ride-share rapist; Jamie and Eddie team up to aid a fellow officer when his partner is shot on the job.

Frank causes family tension when he assigns Jamie to guard Danny after a hit is put on him; Frank tries to stop his grandson from seeking revenge after he's attacked; Eddie gets a hostile new partner.

Jamie and Frank oppose each other's viewpoints over the public's treatment of cops, after rowdy teens pour water on two rookies; Danny and Baez investigate a man who preys on the elderly; Erin is forced to admit her wrongdoings.

The team is hired by the Department of Defense to test the security at Fort Knox by trying to break in and steal a precious artefact.

In Chernobyl, Sylvester and Paige become trapped inside a decaying nuclear reactor that the team is trying to repair before a tragic meltdown.

Jax decides to bring the boys to the cabin. The club struggle with heartache internally and conflict with the organisation at large.

Angie tries to target her mother's illness using a radical technology; Walter, Malik and Zoe attempt to use suspended animation to stop a man's internal bleeding.

A hit man saves a congressional aide from two men posing as NCIS agents; LaSalle struggles with plans for her brother's future.

When Nicholas Helman resurfaces to carry out a killing spree, the team are forced to get help from the one person who knows him best: his protégé, Murdoc.