This fun and light new series is about Misty and her fellow Sisters of the Sea, mermaids who live in the underwater Coral Kingdom. The mermaids have been sent on an important mission by their queen, Neptuna, and the fate of their fellow mermaids depends on their success. Through their adventures, the mermaids learn about friendship, teamwork, and protecting the ocean and its inhabitants.

Just when Ellie and the other mermaids are safely on their way back to Coral Kingdom, the evil mermaid Mantora is brewing trouble again, this time causing an oil spill in the ocean. It's up to Ellie to find a very special ingredient for a potion that could save her fellow mermaids and other sea creatures from Mantora's evil handiwork.