In the fourth and final book in speculative-fiction master Christopher G. Nuttall's Angel in the Whirlwind series, an epic battle pits the survival of hope against the locus of destruction. As the Commonwealth produces more starships and increases recruits, victory begins to slip from Theocratic control. This can only make the Theocracy more desperate to win...and more dangerous to fight. After a mission to liberate an occupied planet ends in nuclear devastation, Kat Falcone-now a commodore in command of HMS Queen Elizabeth-sees firsthand just how far the enemy will go. Suddenly dealing with the war effort and a humanitarian crisis, many in the Commonwealth want a truce. Kat wants something else: to crush the Theocracy outright-and quickly. Kat devises Operation Hammer, an all-out assault on the enemy home planet, Ahura Mazda. It is a bold and risky plan, but the enemy has revealed there can be no middle ground. Can Kat break the galactic stalemate and deal a death blow to the Theocracy? As two empires prepare to fight the largest space battle in history, Kat must trust her instincts to save her people and avoid oblivion.