The gates of hell - P. C. Doherty

In the third magnificent volume in this mystery series it is 334 BC, and Alexander and his troops have crossed into Asia. Marching south he has conquered all in his path, but he and his enemies all know that the great prize is the city of Halicarnassus, strategically important and with fortifications to make any attacker despair. Alexander's court is set up close to the city, and his physician and old friend Telamon is there.

Even as Alexander prepares for one of the most dramatic confrontations in the ancient world, a series of brutal killings begins, proving that the Persians have infiltrated the court. With his lord facing the fight of his life, Telamon must go through 'the Gates of Hell' to find the traitors.