In the final week of February 1944, the USS Grayback was still hunting, and that fact alone tells you something about the boat and the men aboard her. She had already spent nearly a month stalking the shipping lanes of the East China Sea, slipping between patrol routes and aircraft arcs, rising at night to recharge batteries and diving by day into that dim, red-lit world every submariner understands. The air would have been thick with diesel and machinery oil, the rhythm of the engines as familiar as breathing, the routine of watch rotations steady and practiced. Her tenth war patrol had begun on January 28, when she departed Pearl Harbor under Commander John Anderson Moore, and by mid-February she had once again proven herself to be what the Navy built her to be: a long-range predator operating far inside hostile waters.