She slipped beneath the waves with purpose and silence — a steel hunter in a sea of shadows. The USS Pickerel (SS-177) was no ordinary predator. She was a Porpoise-class submarine, forged in peacetime but baptized by war. And in the spring of 1943, she became the first U.S. submarine lost in the Central Pacific — vanishing without a trace in the cold, contested waters off Japan’s northern coast.