Marius' Mules XII: Sands of Egypt

Winter, 48 BC. Caesar and his small force are trapped in the Egyptian city of Alexandria. Caught up in the dynastic struggles of the House of Ptolemy, the consul has sided with the clever and ruthless Queen Cleopatra. Her brother and fellow monarch Ptolemy XIII languishes in the palace, a hostage of Caesar's, while a huge army under the command of the Egyptian general Achillas closes on the city to free him.
With both the future of this ancient land and the safety of Caesar and his men at stake, Fronto and his friends face the terrible task of holding an unfamiliar city under siege, in the desperate hope that reinforcements will reach them before the enemy break in. But Egyptian reinforcements gather too, and with the interference of the youngest princess, Arsinoë, the future is far from written. Trapped, besieged and outnumbered, time is running out for the Romans, as shadows loom across the sands of Egypt