Callan has been retired from an anonymous government agency known as "The Section", run by Colonel Hunter (the name "Hunter" is used as a code name for the current Section Chief, similar to the C of SIS). The Section removes those who pose a danger to the public, using either persuasion, blackmail, extortion or death. David Callan had been the Section's top operative, but had become too curious about his targets and the rationale for their removal. The Section considered him vulnerable, volatile and dangerous, so had laid him off to a dead-end book-keeping job with an ungrateful employer.