An ensemble cast is a method of dramatic production in which all members of the cast have equal amounts of screen time
and importance. The structure of the ensemble cast is complicated because it aims to emphasize the interconnectivity of
characters by unifying different parallel plot lines, and existing story support methods cannot be applied. In this paper, we
propose a system for supporting the scriptwriting with an ensemble cast. We analyze the existing movies with and without
ensemble cast to clarify the difference between them. Our system shows scene compositions extracted from existing
movies, which contains a given number of sub-stories and a given number of scenes. User experiments show that our
system is useful for the scriptwriting with an ensemble cast.