The Church of the Silver Flame is famous for the extermination of the tainted creatures known as lycanthropes (such as werewolves) in Khorvaire.
You have each been summoned for your famed skills and expertise. The Church cardinal has discovered a hidden enclave of deadly lycanthropes, known as the "Six" operating in the City of Sharn. These menaces have somehow hidden their nature and managed to infiltrate the government.
They need to be eliminated quietly, before they can complete whatever evil deeds they are plotting. Of course, it needs to be done carefully, as there are some who do not realize how deadly lycanthropes are. In addition, there is the danger that the others might hear of the attacks and escape before we can catch them.