When wealthy banker Francois Jourdain starts spending his money on philanthropic causes, his relatives have him committed to a psychiatric clinic to save their inheritance. During Mardi Gras celebrations, Jourdain escapes and takes residence in a boarding house inhabited by several miserable individuals, including Lydia, the suicidal Russian Fedor, and bitter old spinster Miss Aglae. Francois hires some actors, led by Deribin, to take up residence there and cheer up the inhabitants by putting on a musical production of ''Quo Vadis''.