Madison and Valerie are in trouble! Beatrice and Will must search for the Magic Mirror to find out what happened!
Madison and Valerie face their sea monster kidnappers as the humans embark on a quest to find their lost mer-friends!
Madison and Valerie must figure out what mermaid song will open the magic lock to the well of power while Jed pays some old friends a visit.
Madison, Valerie and the sea monsters come up with a plan to get a whale song into the well of power while the gang lands in Indonesia to begin their search for the mermaids.
Valerie must learn an ancient technique in order to open the octopus lock while Nat and Liam have to fight their way to getting the magic ring.
Madison and Valerie must battle Ronan and Petromey to unlock the next stage of the well of power while Stanley and Will look for the ghost of a mermaid to help them translate the magic ring.
The final lock has the Mermaids confused as the humans get closer and closer to finding the location of the lost Mermaids!
United, the Mermaids, humans, and sea monsters figure our how to open the final lock on the well of power, but something goes wrong!
The Mermaids, Humans, and Sea Monsters come up with a plan stop Will's dad from stealing the worlds magic!
In the season 4 finale, the mermaids, humans and sea monsters must unite to stop the magic well from destroying everything in its way!