4. "Speed Saunders: The Mystery of San José Island", "Cosmo, the Phantom of Disguise: The Rajah's Ruby", "Buck Marshall: Death Message", "Bruce Nelson: The Claws of the Red Dragon (Part 4 of 8)", "The Bumps Mystery", "Bart Regan, Spy: The Balinoff Case (Part 4 of 5)", "Mr. Chang: The Bloody Will", "Slam Bradley: The Hollywood Murders"

In March 1937, Speed Saunders embarks on a dangerous mission to investigate the murder of his old friend, Arthur Bell, foreman of the Allied Sugar Plantation on San José Island. Against the orders of his superior, Mr. Marr—who fires him for pursuing the case—Speed rents a biplane and flies to the remote island, located just south of Cuba.