Winter 1793 - the Reign of Terror rips through revolutionary France, as every able-bodied man is pressed into military service. The city of Toulon has turned itself over to the British - the red ensign of Lord Admiral Hood's flagship, Victory, offering a defiant symbol of protection to its people. In Plymouth, Master and Commander Charles Hayden is summoned to the port admiral - his orders are to return to the ill-fated frigate, HMS Themis. Placed in temporary command, he is to join the escort for the last convoy of the season - braving the wintry seas to supply Hood's fleet in the Mediterranean. Hayden's uncanny knack for attracting the attention of the French navy sees the Themis thrown back into action only hours out of port. Soon, Hayden's captaincy and military skill are stretched to their utmost as he finds himself at the vanguard of this brutal clash of empires.