On hearing of the death of his only son by the sword of Paul DĂ©roulede, the Duc de Marny forces his daughter Juliette to swear an oath to ruin DĂ©roulede in revenge for her brother's death. Having tricked her way into DĂ©roulede's home Juliette denounces her host, but realizes to late that she has come to love the man she has vowed to destroy. She will need a help of Scarlet Pimpernel to save the day.