Callan (TV series) is run by Colonel Hunter. ("Hunter" is a pseudonym for the current Section Chief, like the C of SIS.) The Section removes those who pose a danger to the "innocent" by persuasion, blackmail, extortion or death. David Callan had been the Section's top operator but he had become too curious about his targets and the rationale for their removal. The Section considered him vulnerable, volatile and dangerous and had laid him off to a dead-end book-keeping job for an ungrateful employer. ABC then commissioned a series of six episodes in 1967. In the first episode Callan rejoins the section in
Callan (TV series) Television had, via an enforced merger, become Thames Television. A second series of fifteen episodes that had already been completed by ABC was therefore transmitted by its successor. This run ended with "Death Of A Hunter", in which the Section chief meets his demise, and Callan is shot – perhaps fatally. It had not been decided whether the show would return for a third series, so this device was used to leave open either the possibility of more stories in the future, or a way of winding-up the show. Two endings were taped, in which Callan either lived or died.