Scott Hunter is an unemployed code-breaker.
Unemployed because having graduated from university with a 2-1 in Mathematics, Hunter had discovered much to his dismay and even more so for his girlfriend and roommate, Amy, there was not a huge demand for math grads in the work force.
The code-breaker part comes from a fascination (Amy would likely call it an obsession and she would be closer to the truth) with cracking any type of code. We are told early on in our introduction to Hunter that his love of the history of code breaking had taken him from the year days of Babbage and Kasiski up through time to the work at Bletchly Park and Hunter's latest avocation - breaking the Enigma codes.
Apparently there were still large numbers of unbroken coded messages left over from the end of the Second World War and Hunter was enjoying the painstaking work of cracking these, even as he supposedly was searching in earnest for a real job. He had even go so far as become a member of an ad-hoc group that called itself Enigma and whose members routinely exchanged emails about this activity.
This fascination with and impressive skills at breaking these codes will change the life of Scott Hunter in ways he never expected while ending the lives of some people very close to him. This will be caused by the interest into Hunter's activity by one person, a man going by the almost foreboding name of Lazarus.
Scott Hunter is not a trained agent; he is a normal person with a gift for code-breaking. Unfortunately, he will wish he either was trained or did not have that gift.