When Sam's friend Tom Olsen finds himself being hunted down by enemies from his past, the NCIS team must find out who is after him.

When a young, non-verbal boy is found hiding in a stranger’s garage, the CSI team searches for his missing mother. Also, Max receives a strange letter with symbols in silver ink that Folsom and Allie recognize from prior crime scenes.

A suicide shakes the staff. Dr. Choi and Dr. Halstead face off over how to treat a patient with stroke symptoms. Family turmoil unfolds when a boy is treated after falling in a river. The importance of learning from mistakes is emphasized to Dr. Reese.

The BAU is interviewing different candidates to join their ranks in the wake of Kate’s departure, including a forensic psychologist, Dr. Tara Lewis, who is eager to assist their efforts. Also, the BAU hunts for a serial killer who leaves behind distinctive evidence that points to someone intent on revenge.

In the aftermath of the Walker’s dramatic Thanksgiving dinner with Abeline’s (Molly Hagan) traumatic hospitalization, the family rings in the new year with members of the Walker family resolving to make better choices across the board. While Cordell (Jared Padalecki) throws himself into family matters, Cassie (Ashley Reyes) pulls Trey (Jeff Pierre) into a case tracking down an elusive tech mogul. But Cassie gets the sense she’s in hot water with Captain James (Coby Bell).

After being tipped off about a woman running barefoot through the woods, Intelligence is led to a kidnapping victim locked up in a shipping container. The bizarre scenario leaves Voight questioning the legitimacy of the case, and sends the team on a twisted trail to get to the bottom of it.