Merpeople won the fight to get their rights back, but many humans aren't thrilled to welcome their infected counterparts back into society. The burden lands on Amy and Tom to fight for the refugees' place on land once again. Meanwhile, orphaned Grayson is just trying to survive middle school as a mythical creature when things take a turn for the worse. Young humans begin to show up Cursed, merfolk begin to disappear, and trouble brews at The Sanctuary. The adults are keeping secrets, so it's up to Grayson and his friends to figure out what's going on before merpeople are wiped off the face of the Earth - forever.