Ellie and her friends are on their way back to Coral Kingdom with the magic crystals for Queen Neptuna, when a storm is whipped up by the evil Mantora which throws them right off course. Ellie 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. Ellie must find a very special ingredient to add to her potion to help her mermaid friends, as well as saving a group of sea gulls from a sticky end.