In June 1793 Captain Richard Bolitho arrives at Gibraltar to take command of the Hyperion, a seventy-four-gun ship of the line. Although not completely recovered from a serious fever contracted in the Great South Sea, Bolitho is eager to get back to duty against the rising might of Revolutionary France. He sails to join Lord Hood to partake in the Monarchist-inspired occupation of Toulon. But at heart Bolitho is still a frigate captain, and he is soon fretting at being tied to the fleet's apron strings; his ship, too, is old and slow, her hull weed-encrusted after nearly four years' continuous commission. Beneath the Mediterranean sun, and often in sight of the enemy coast, Bolitho and his tired old ship face one conflict after another – and when at last the ill-fated campaign collapses in failure it is the Hyperion, outgunned and outnumbered, which takes her rightful place in the line of battle.