Three years after the legendary tide-opera director Sirena vanished, Nerissa Thalassa lives as the voiceless wife of Lord Cassian Drake, hiding her crown, mermaid tail, and royal voiceprint. When Cassian saves his widowed sister-in-law Marina instead of Nerissa during a staged drowning, Nerissa files to dissolve their Sea Vow and returns to Tide Palace. She revives The Endless Ocean, the unfinished work connected to her grandmother's First Memory Shell, while separating Drake capital from casting and creative control through Tide Escrow and the Director Conch. Marina escalates from gossip and forged pregnancy claims to theft, Siren Venom, manipulated Tide Mirror footage, and an attack on the Seven Seas Crown Gala. Nerissa answers with professional skill, medical evidence, original voiceprint records, lawful procedure, and her own authority. In the finale, the world learns that Nerissa is both Sirena and the heir to Thalassa Crown, and she refuses to make romance the reward for reclaiming her voice.
