A trilogy conclusion finds Byx and her friends discovering that the same extinction facing the dairnes is threatening all living species, prompting the team to recruit creatures throughout the world into their revolution.

Every night Lampie, the lighthouse keeper's daughter lights the lantern which warns the ships away from the rocks, but when the light goes out one night, a ship is wrecked and Lampie is sent to the Admiral's Black House in disgrace--there she finds and befriends the Admiral's son, who was born with a tail, and together they are pulled into an adventure of mermen and pirates, and secret identities long concealed but soon to be revealed.