Video: The Vanishing Trailer (1988)
Excerpt from IMDb.com: The central plot of the film (and the novel on which it is based) is from an archetype Urban Legend related to the Paris Exposition of 1901. A woman and her daughter travel to Paris for the exhibition, and whilst the woman unpacks, the daughter goes to a nearby shop. When she returns to the hotel, the mother is gone, and no one in the hotel remembers having seen her. The idea also formed for the basis for Alfred Hitchcock's The Lady Vanishes, Terrence Fisher's So Long at the Fair, Robert Fuest's And Soon the Darkness and Philip Leacock's Dying Room Only.
Link to the Imdb.com record : http://www.imdb.com/title/tt0096163/?ref_=sr_2