Nemesis

Miss Marple is called upon to solve her most perplexing case yet. Upon his death, financier John Rafiel asks her to solve a murder. Only problem is that the murder may or may not have place as yet and the victim is unknown. All that he has given her is two tickets on the Daffodil Tour Company's Mystery Tour. It soon becomes obvious that others on the tour were also "selected" by Mr. Rafiel. (imdb)