Ethan Caldwell opens his eyes as Baldwin IV, the infamous leper king of 1177 Jerusalem, armed with modern knowledge in a medieval world. Through ingenious innovations—hwachas, windmills, and advanced crossbow designs—he reshapes the balance of power in the Holy Land. His audacious campaign to seize the Sinai Peninsula pits him against Saladin's legendary forces, as he harnesses cutting-edge strategy to rebuild and fortify the crumbling Crusader states into an unprecedented empire.