The Mole is the fourth episode of the third season. It was released on 13 October 2006.
The hit-and-run death of a Chinese interpreter suddenly compromises a team member, and throws the entire unit into disarray. Charlie, meanwhile, must deal with not being consulted by Larry for a paper the older man published.
- A commonly used term in spy fiction to denote a double agent, one with twisted loyalties and an internal rationale. Turning or 'flipping' moles is often crucial in the uncovering of enemy spies within one's own network, and thus a vital element of counter-espionage.