Callan - Season 0 Episode 1 Wet Job

Ten years on, David Callan hasn't changed much. Retirement has brought a new identity, a new mistress, and a new business in the form of a militaria shop. But once a secret-service operative, always a secret-services operative, as he discovers when a call summons him to headquarters and a meeting with the fourth 'Hunter' of his career. Callan thought the past was dead and buried - reactivating it is no pleasure, but it has to be done.