 On hearing of the death of his only son, the Duc de Marny (by now a cripple and almost a dotard) is distraught.The Duc summons his fourteen-year-old daughter, Juliette, to his side and forces her to swear an oath to ruin Déroulede in revenge for her brother's death, telling her that her brother's soul will remain in torment until the final judgement day should she break her promise.The story picks up ten years later, and Citizen Déroulède, though no longer rich, is a lawyer popular with the people and is allowed to go his own way, for Marat has said of him ""Il n'est pas dangereux"".