Charlie Harrison finally achieves his dream of commanding the Sandtiger, leading her able crew on a war patrol to the Philippines in September 1944. Along the way, he faces the challenges of command, a malfunctioning boat, and a patrol area that appears devoid of enemy ships. When a massive fleet materializes on the horizon, he identifies it as Admiral Halsey's Third Fleet. America is invading the Philippines to cut off Japan from its colonial resources. The Japanese Combined Fleet responds, culminating in the largest naval battle in history and Charlie facing the ultimate test.