Colonel Holman Stevens, the railway magnate, has called upon the services of Sherlock Holmes to investigate the ongoing thefts from his Pullman trains, which are believed to be the work of a ruthless gang. Meanwhile the mysterious Captain Basil, a famous explorer, is on board a Pullman train returning to England with a valuable haul of gold coins, which he is to present to the British Museum. A murder follows but the body appears to be that of an innocent passenger, one Doctor Dietler.
Who is Captain Basil? Why was a murder committed? What is the motive for the subsequent blackmail aboard the train? Join Sherlock Holmes and Doctor Watson as they unravel no less than three crimes in this complex case.