One evening while out on a walk, Christian Lespinglet saves Boudu, a homeless man about to commit suicide by jumping into a river. Lespinglet brings him back to his place and, despite resistance from his wife Yseult, agrees to put him up for awhile. It doesn’t take Boudu long to throw his host’s life into disarray. He lights a flame in Yseult which was extinct for a long time. This leaves Christian free to court his assistant,
Coralie.
However, she too falls under Boudu’s charm. As if that were not enough, Christian’s business begins to fail. With his life falling apart at all ends, the desperately unhappy Lespinglet goes to the river where he saved Boudu and contemplates jumping into the water.