The murders are committed in swift succession on board a liner crossing the Atlantic in a dense fog, and many of the passengers come under suspicion before the actual killer is bought to justice with the aid of a very substantial "ghost."
as Mary Fulton
as Wentworth Brown
as Dr. Winstay
as Alonzo Holt
as Madame Alva
as Mrs. Jackson
as Mullaney
as Ship Captain
as Dickens
as Mrs. Bentley
as Ship's Doctor