The tree of life - Christian Jacq

In the temple of Abydos, an acacia tree is dying. And its death threatens all of Egypt. For this is no ordinary tree: it sprang forth from the tomb of the god Osiris, the first ruler of Egypt, as proof of his triumph over death. The great pharaoh Sesostris III immediately joins battle against the invisible enemy who wishes to lead Egypt to her doom. But unknown to Sesostris, within his closest circle hides a traitor, a man who dreams of power and glory, a man who will sell himself to the powers of darkness in order to achieve his aim.
A young apprentice scribe, Iker, becomes an unwilling player in this mystery. Kidnapped by sailors who refer darkly to a 'state secret', Iker does not know who is trying to kill him, nor indeed who is trying to protect him. Haunted by a vision of a beautiful young priestess, Iker senses that someone is guiding or manipulating him, and that he has set out on a road whose end he does not know.
Will the two of them, Iker and Sesostris, the weak young boy and the great man of power, succeed in preventing Osiris from dying for the last time, thereby saving Egypt?