A girl torn between two worlds . . .

Turtle is scavenging a drowned town when she saves a stranger's life. There's something special about Kai--an attraction she's never felt before. She would do anything to see him again.

But Turtle can never truly be with Kai, because Kai is Normal, and Turtle is one of the Mer, kids whose genes were illegally hacked before birth and who now have working gills as well as lungs. Turtle lives on an old cruise ship with the other Mer in order to be close to the water she needs to survive.

Yet she sneaks away and lies to her friends to spend more time on land with Kai. And the pull of the shore grows even stronger when Turtle reconnects with her sisters and learns that her father, who has been in prison for having her genes modified, has escaped and may be hiding out nearby.

When scientists come up with a way for the Mer to surrender their gills and live as Normals, Turtle faces a terrible choice. Turtle loves her life with her Mer friends, but she desperately misses her family. And then there's Kai . . .

Should she give up her Mer community and their way of life, along with the joy of living freely under the sea? Or give up the guy she's falling for . . . and any hope of reconnecting with her family?