The Wheel Spins — Ethel Lina White

First published in 1936 and adapted for the screen as The Lady Vanishes by Alfred Hitchcock in 1938, Ethel Lina White's suspenseful mystery remains her best-known novel, worthy of acknowledgement as a classic of the genre in its own right.

Then the rhythm of the train changed, and she seemed to be sliding backwards down a long slope. Click-click-click-click. The wheels rattled over the rails, with a sound of castanets.

Iris Carr's holiday in the mountains of a remote corner of Europe has come to an end, and since her friends left two days before, she faces the journey home alone. Stricken by sunstroke at the station, Iris catches the express train to Trieste by the skin of her teeth and finds a companion in Miss Froy, an affable English governess. But when Iris passes out and reawakens, Miss Froy is nowhere to be found. The other passengers deny any knowledge of her existence and as the train speeds across Europe, Iris spirals deeper and deeper into a strange and dangerous conspiracy.