A traveler walks into a roadside inn in France. (Sounds like the beginning of a joke, right?)
At the inn, the landlady and some customers are talking about Rigaud's case – the newspapers say that he was acquitted and released.
Someone brings up the idea of "philosophical philanthropy" – the idea that there's no difference between morally good and bad actions or people, but that instead actions and people should be judged according to whether they increase the general well-being of humanity. This is a very easy standard, as you can imagine. Nothing subjective about figuring out what the well-being of all humanity consists of. (We're being sarcastic, if you can't tell.)
The landlady is all, "um, no, some people are bad and need to be killed off."
Anyway, the traveler is clearly Rigaud, but he doesn't identify himself. From the conversation it's obvious that he has just barely escaped mob violence in Marseilles.
He gets a bed for the night but has to share the room.
When he gets upstairs, he finds that his roommate is none other than... Cavalletto!
Of all the gin joints, in all the towns, in all the world, he had to walk into... uh... we mean, that's a crazy coincidence!
Rigaud wakes up Cavalletto, says that his name is now Lagnier, and tries to get Cavalletto to be his servant again. As incentive, Lagnier threatens to tell everyone that Cavalletto was his cell-mate, implying that this way they'll both be lynched. But offering all sticks and no carrots is a poor managerial technique, as any boss will tell you.
Rigaud/Lagnier goes to sleep.
Cavalletto gets dressed, waits till Lagnier is asleep, then creeps out the door and runs away from the inn as fast as he can.