Casey Collins is an analyst in the U.S. State Department.
An experienced Foreign Service officer, she is, at the start of the series, working the terrorism desk and helping track the comings and goings of known terrorists, monitoring carefully for not only acts but potential targets of acts.
Initially a very junior FSO attached to the American embassy in Warsaw, she became friendly with a Polish language teacher who turned out to be an undercover agent for the Danish Defense Intelligence. This man, named Stefan, brought to her news of an upcoming plot by rising terrorist star, Abu Nidal. Carefully she and her bosses studied the information, and the courier, and became convinced it was valid. From that moment on, her career changed.
Once Stefan's real identity became known and he returned to Denmark, their relationship grew to become lovers. For a while she considered leaving her employers and joining Stefan and his boss' anti-terrorist crusade. She even took extensive field training. In the end, though, she felt her place was in America, working for the State Department. Since then, she has become one of the leading authorities at State in terrorism.
Collins learns the hard way that being a darn good analyst and expert in the patterns of terrorists and extremists is quite a bit different from the world of a field agent with the enemy breathing down the neck and bodies shot and strewn about. She also learns that she has what it takes to survive, if she can just live that long.