At the castle of the Duke and Duchess of Belleroche, Baronness Héloïse de Montargent is found murdered, a ruby-encrusted dagger plunged into her heart. Captain Valère Florentin investigates, but behind the splendor of the court, everyone hides their own secrets.

Baron Séraphin, the victim’s husband, is having an illicit affair with Basile, a painter as talented as he is notorious. The Duke and Duchess manipulate power and emotions, Elvira the singer whispers to the powerful, and the Corsair Ezequiel pulls the strings from the shadows, alongside Ysée the Red, a feared pirate. Isolde the Archer, secretly the Duke's spy and the captain's lover, was the last to meet with the Baronness... but she died before she could speak.

In this web of deceit, everyone has something to hide... and to lose.