This is the story of Alex, a head tailor in a Paris department store, who was laid off a year ago. As a result, his wife has left him, he has had to vacate his apartment and he has found part-time work, guiding tourists around the Paris sewers. His only shelter is the room in the basement of his building where the trash is kept, a place he has been able hold onto thanks to the complicity of the janitor who is very fond of him. His every belonging is stocked there. To alleviate his loneliness and accommodation problem, Alex has got into the habit of choosing an apartment every night in Paris, wherever his steps lead him, and getting himself invited for the night. He vertually always succeeds. For some time now, a shadow has been following him everywhere and accusations of theft in apartments visited by Alex have been flooding into the local police...