Sam helps an Afghani elder and former friend search for his missing nephew; Callen worries that Sam is overly invested.
The team keeps trying to rescue Betsy Blane from Syrian captors; Mack has an opportunity to get revenge on Ryan for his affair with Tiffy.
During an investigation into a suicide bombing at the U.S. Marine base, a discovery is made about a new, chemically undetectable bomb material; Gabriel is unable to finish a task.