Detective Conan S01 E410 The Simultaneous Stage Advance and Kidnapping (2)

"One truth prevails."

The time of show is getting closer, Tamanosuke decides to play the show without Renge Kataoka, the actress, by replacing Ran as the girl before the end of the show. Thus Conan manages to find out who has kidnapped the girl and free just in time to enable it to play its role in the show.