Just as Holly and her friends start to make their way back to Coral Kingdom with the magic crystals for Queen Neptuna, a storm whipped up by the evil Mantora, throws them right off course! Holly and her fellow Sisters of the Sea are lost, but they must find their way home as quickly as possible in order to complete their important mission. Holly must be very brave so she can help her mermaid friends, and save the turtles's home from danger.