Prologue: The murderer "Boss" Huller - after having spent ten years in prison - breaks his silence to tell the warden his story. "Boss", a former trapeze artist, and his wife own a cheap side-show that displays ''erotic sensations''. But he longs for his former glamorous life in the circus. When he meets the orphan Berta-Marie, he falls under her spell and leaves his wife and young son behind. He makes Berta-Marie his partner in a new trapeze number. One day, the famous trapeze artist Artinelli takes note of them and engages them for his trapeze show in Berlin. Their salto mortale becomes an immediate sensation. Calculatedly and cold, Artinelli seduces Berta-Marie and destroys "Boss'" happiness.