The Wheel Spins (The Lady Vanishes) is a mystery novel by British writer Ethel Lina White.
Iris Carr, a young English society woman, is staying at a small hotel in `a remote corner of Europe'. Her friends leave on the train to Trieste. Iris is glad to be alone, but then starts to miss them. The remaining guests are also glad to see them leave, due to their noisy ways and monopolising of the hotel facilities. After going for a long walk and getting lost in the local mountains, Iris decides to leave also, but waiting at the railway station, she is struck or hit on the back of the head and loses consciousness. She wakes up in the waiting room, but as she can't speak the local language, no-one can tell her what happened. She concludes that it must have been sunstroke, but manages to get on the crowded train. She finds herself in a compartment with only one English speaker, Miss Winifred Froy.
Miss Froy explains that she was a teacher of the children of a local aristocrat. His widow, the Baroness, is also a passenger in the compartment. Fellow hotel guests, the Reverend and Mrs Barnes and the Misses Flood-Porter are also aboard the train. She spies a heavily bandaged body in another compartment, supervised by a sinister-looking doctor apparently taking an accident victim to hospital in Trieste.