Julius Caesar is dead, and the lives of two teenaged boys are about to be changed forever. One is Caesar’s 17-year-old nephew, Octavius, whom he has made his heir.

The other is Octavius’s closest friend, Agrippa.

To claim Octavius’s inheritance, they must fight the giant figures of the Roman Empire – and, against all odds, they win. Octavius becomes the Emperor Augustus. For twenty years, they rule the world together.

Now Agrippa is fifty. Ailing and alone, betrayed by his wife’s infidelity, he takes refuge in his house on the Bay of Naples and begins to write his memoirs. Yet to stir up the past can be dangerous. From his earliest meetings with Julius Caesar, through the epic conflict with Mark Antony and Cleopatra, the great naval battle of Actium and the endless wars to expand the empire, he describes how one man has dominated his life: the cunning, ruthless, unknowable Octavius.

When it comes to power, does friendship exist at all?