Each week there would be a new top-secret mission. The spy organization would bring in new operatives to accomplish specific tasks during the mission-of-the-week. Instead of highly-trained agents, they would find a civilian who was an expert in a field. For example, if the job involved somehow planting a bug in a persons house, they might employ a plumber who would be able to figure out how to get the bug in via water pipes). The episodes usually started with a briefing of the new spies, which helped the viewer figure out who could do what.
Dan Newcombe <email@example.com>