A body left in a field prompts the examination of pollen, establishing a new forensic discipline, and fibres fused with car wreckage prove who caused a fatal traffic collision.

When it becomes obvious that a forensics expert raped and murdered a student, the investigation focuses on a criminology professor Cragen arrested decades earlier for similar crimes, and it’s up…

Eric witnesses his friend, a computer systems expert, being attacked by people who want information that could redirect a missile; Kensi runs into a familiar face in Afghanistan.