When a Naval engineer is murdered, the team struggle to find a motive related to the killing and they soon come to the conclusion that international espionage might be a primary motive. However they get a huge shock when NCIS Forensic Scientist Abby Sciuto arrives in Los Angeles with the belief that the engineer may be the victim of a serial killer known as the Phantom whose M.O is kill his intended target and leave no evidence of any kind behind...
It's revealed that Hetty has changed the structure of the bullpen by giving it a good cleanout and also assigning the members of the OSP new seats.
The team meet Abby in person for the first time.
Eric reveals that he knows sign language and that he's been learning it since he was seven years old.
It's also revealed that Callen is the head agent of the team.
Trivia[]
The episode name "Random on Purpose" refers to the manner in which the Phantom kills, which Abby herself refers to as "random on purpose".
This episode also marks the final appearance of Abby Sciuto as she has not been seen or heard from since then. It's presumed that it was the Major Case Response Team feared that she would get kidnapped again so Abby has not returned to Los Angeles since then and it's believed that her appearances were just a one-off and only centered around Season 1.
When you freeze frame on Abby's letter she's sending, near the end it says "Naval Investigative Criminal Service" (NICS) when it's actually NCIS.
While interviewing Ted Brock, Callen tells him that he has two outstanding arrest warrants against his name where it's actually three.