Hell's Gate

When a Japanese submarine is found abandoned deep within the Brazilian wilderness during World War II, a resourceful zoologist named Captain R. J. MacCready is sent to investigate a mysterious and potentially catastrophic plot. As he explores the remote jungle and reunites with old friends, Mac uncovers an sinister Axis plan to attack the United States, while also confronting a dangerous biological threat lurking in the shadows. The story combines adventure, scientific intrigue, and a race against time to prevent disaster.