Nick Winter is an agent of MI-6.
Well, technically when we first meet him he is an ex-agent and was working as a "tracker and finder of terrorists for the highest bidder". Our introduction to him comes as he is in India on a contract for three basic reasons: 1) his funds ran low and the money they offered was good, 2) India was hot and London was cold, and 3) there was international tennis and a cricket test-match in Mumbai. Such are the kind of reasons Winter uses for taking an assignment.
We learn from an intro on Winter that he is "a keen scholar in Eastern history, religion and politics". He is "scarred by racial prejudice due to his mixed British/Indian parentage". And three interesting facts that will pay a part in his adventures: he "doesn’t like taking orders, doesn’t like confined spaces, and definitely doesn’t like being taken for a fool".