In this all-new, fast-paced tale of lost treasure and mistaken identities, young treasure hunter Fish—nicknamed for his swimming abilities—learns that his refusal to fight has a cost when he's torn away from his pirate family. Fish and his friends Nora and Daniel are forced to sail under Countess Marie de Bornholdt, the widely feared and very unusual captain of the Rat Queen, and her first mate—Fish's archnemesis, Scab.
In search of the storied ship with emerald eyes, the Rat Queen's treasure hunters race from the islands of the Caribbean Sea to the canals of Venice and the sunken library of a cursed duke. Yet they're not the only pirates on the trail. After an unusual map leads them to a mysterious island, the line between friend and foe blurs, forcing Fish and his friends to make a terrible choice.