After their daring escape from Syrellian, Cari settles into her life in Piscea with her sisters. Each of the merfolk kingdoms face challenges as they fortify against his inevitable retribution. Kallan is determined to rescue Adamaris from Syrellian before Varan uncovers the truth - that he is the one leaking vital information to stop the Mad King. Meanwhile, Adamaris fights to protect his little sister, betrays his father, and uncovers shocking secrets that threaten everything he knew about their kingdom's past. The Sea Witch continues to pull strings, endeavoring to shift things in her favor by making friends with Prince Evander's new bride, Lady Eunji.