Mythological assassin vs detective.
Mythological in the sense that he has a fancy name tying in to the history surrounding that particular assassin.
In this case, some perhaps not so nice people want a French leader removed, and haven't managed it themselves, so they bring in an outside expert.
On the other side is a detective trying to track him down.
An excellent example of tense spy thriller writing of the time, by one of its foremost proponents.
4.5 out of 5