Heading home from holiday, young Iris Henderson (Margaret Lockwood) befriends the elderly Miss Froy (May Whitty) on a transcontinental train ride. After Iris awakens from a bump on the head, she finds that there is neither hide nor hair of her new friend, and no one else on the train can--or will--acknowledge the woman’s presence. With help from a single supporter on board (Michael Redgrave), Iris begins a dangerous search for the truth. Superlative Alfred Hitchcock whodunit co-stars Paul Lukas. 97 min. Standard; Soundtrack: English.