Sam Archer is a member of the NYPD Counter-Terrorism Unit.
Well, not at first. In the first three recorded adventures, Archer is a member in good standing with Britain's Armed Response Unit, an elite group put together to be a rapid responder to any crisis remotely involving terrorism. The members do not exactly have a license to kill but they can and do shoot without hesitation when necessary and when the unit gets called into action, it is usually necessary.
As the series progresses, Archer will leave his post with the ARU and take a job with the New York Police Department. Through his late father, a decorated NYPD detective, Archer enjoyed dual citizenship and the job offer in the States was compelling though it came only after a particularly harrowing off-books mission.
With the CTU, Archer is most definitely in his element. He is a man of action and with the Big Apple being such a magnet for all kinds of nasty miscreants, his life is never dull. Unfortunately, though, it is also never peaceful so having anything close to a normal life is something that is constantly proving to be a problem.
At times, though, Archer will be pulled back into his old realm and a time or two thrown into totally different circumstances which keep him on his toes and keeps the action going strong. Luckily for him, when he is home, whether during his ARU days or his new CTU adventures, he is joined with people who, though quite a bit different than he, are every bit as interesting. And dangerous.