334 BC. Alexander the Great is just twenty-one years old when he sets out with a small army to challenge Persia, the largest and most powerful empire in the world. Together, his Macedonian army marches East into the unknown - winning battles against overwhelming odds, storming impregnable fortresses from the Aegean through to India. But there is another Alexander. Prince of the Macedonian royal house of Lyncestis, he becomes Alexander the Great's general and most trusted friend. Alexander of Lyncestis is torn: between this friendship and the duty to avenge his murdered brothers. And he is under threat, too. Others - Persians, Greeks, Macedonians - see him as a rival for the throne. For six years of conspiracy and battle, his life hangs by a thread. For Alexander of Lyncestis is the Shadow King.