Ride with the tide! Deep beneath the waves, King Triton's powerful trident has passed through the magical barrier that surrounds the Isle of the Lost-keeping villains in and magic out. And when Mal's longtime rival Uma, daughter of Ursula, gets wind of this, she can't believe her luck. The tide has dragged in something good for a change, and Uma is determined to get her wicked hands on it. But first, she needs a pirate crew. A storm is brewing back...

Mal, Evie, Carlos, and Jay have received threatening messages demanding they return home. They have a sneaking suspicion that their villainous parents are behind the messages, and something Evie sees in her Magic Mirror confirms their fears. Although Maleficent's just a tiny lizard after her confrontation with Mal, could she have found a way to escape? Mal and her friends determine to sneak back to the Isle to get to the bottom of the mystery.