: In the season premiere, "Under Siege," Hetty sends Nell a text containing only "1D4D52C4" . Owen Granger explains this is a series of chess moves representing the Queen's Gambit , a strategy where a pawn is sacrificed for an advantage—foreshadowing Hetty's plan to "confess" to being the mole to protect the team.
: In "Parallel Resistors," a student named Nadia sends a text from her cell phone that allows Eric to triangulate her location , enabling Callen and Sam to rescue her.
: During the resolution of the mole storyline in "Payback," Eric uses a chain of text messages found on a deceased assassin's phone to track and locate Kensi, who had been kidnapped by CIA rogue operatives.
In of NCIS: Los Angeles , several key plot points revolve around text messages and cryptic communications that drive the central "mole hunt" and rescue operations: