Runa will not let her twin sister die. Alia traded her voice to the Sea Witch for a shot at happiness with a prince who doesn’t love her. And his rejection will literally kill her—unless Runa intervenes. Under the sea, Evie craves her own freedom—but liberation from her role as Sea Witch will require an exchange she may not be willing to make. With their hearts’ desires at odds, what will Runa and Evie be willing to sacrifice to save their worlds?