In exchange for the return of her magic comb, the mermaid promises the boy that no one in his family will ever drown.

"Orphaned as a young child, Mirin O'Malley has been brought up by her grandparents on their isolated, rambling estate Hob's Hallow. Long ago her family prospered due to a deal struck with the mer, the terrifying creatures who live in the depths of the sea: safety for their merchant ships in return for a child of each generation. But for many years the family have been unable to keep their side of the bargain and their fortunes have suffered as a result....

"Locklyn Adair has never fit in. The legs she inherited as a result of her great-great-grandmother's curse make it impossible for her to belong under the sea. When her niece is also born without a tail, Locklyn is determined to save her from similar rejection by sending her to the only place in the Undersea Realm where legs are acceptable--the Lost Island of Atlantis. Darin Aalto would do anything to protect his family, even spearheading an impossible...