Descendants novels (Melissa de la Cruz)

Imprisoned on the Isle of the Lost, the teenaged children of Disney's most evil villains search for a dragon's eye--the key to true darkness and the villains' only hope of escape.

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...