The plot of Hitchcock's film differs considerably from White's novel. In "The Wheel Spins", Miss Froy really is an innocent old lady looking forward to seeing her octogenarian parents; she is abducted because she knows something (without realising its significance) that would cause trouble for the local authorities if it came out. Iris' mental confusion is due to sunstroke, not a blow to the head. In White's novel, the wheel keeps spinning: the train never stops, and there is no final shoot-out. Additionally, the supporting cast differs somewhat; for instance, in the novel, the Gilbert character is Max Hare, a young British engineer building a dam in the hills who knows the local language, and there is also a modern-languages professor character who acts as Iris's and Max's interpreter who does not appear in the film. The cricket-obsessed characters Charters and Caldicott were created especially for the film and do not appear in the novel.