a film characterized by scenes of great tension, danger, adventure, suspense, or high drama, often climaxing at the end of a film, or at the end of a multi-part serial episode, where the plot ending and the fate of the protagonist(s) are left unresolved; the name was derived from the movie serials of the 1930's where each week the hero (or heroine) was perilously left dangling from a cliff -- with a 'to- be-continued' ending -- to increase interest for the next episode (sequel).