When Neptune tells Emily and her merman father and human mother to return to Brightport to try to make merpeople and humans work more closely together, Emily faces problems with old enemies, her new, half-merfolk friend Aaron, and a mystery related to a group of legendary lost sirens.

Ramya Knox is used to feeling cursed. People only notice her long enough to call her a troublemaker. Except Grandpa. He sees Ramya and her neurodiversity as enchanting. But when Grandpa dies, Ramya's world loses its charm...until she discovers he left behind one big secret: that magic is real and Ramya can see it. Trolls, vampires, kelpies, and more fantastical beings hide in the shadows for Ramya to discover. But the Hidden Folk need protection from...