Set in Berlin during the Weimar Republic in 1931, under the presence of the growing Nazi Party, the film is loosely based on the 1966 Broadway musical "Cabaret" by Kander and Ebb, which was adapted from Christopher Isherwood's semi-autobiographical novel "The Berlin Stories" (1945) and the 1951 play "I Am a Camera" adapted from the same work. Only a few numbers from the stage score were used for the film; Kander and Ebb wrote new ones to replace those that were discarded. In the traditional manner of musical theater, called an "integrated musical", every significant character in the stage version sings to express his or her own emotion and to advance the plot. In the film version, the musical numbers are entirely diegetic. All of them take place inside the club, with one exception: "Tomorrow Belongs to Me", the only song sung neither by Grey's character of the Kit Kat Klub's Master of Ceremonies nor by Minnelli's character of Sally Bowles.