Alice Rosier arrives in Brisbane with a secret — she’s already a mermaid. When strange storms begin forming near Mako Island, Cleo, Emma, and Rikki realize she’s one of them. But Alice doesn’t just control water — she commands the sky. As her powers grow stronger, so does the attention of Rafe Cameron, a boy drawn to storms and the girl who creates them. Secrets rise. Feelings build. And Mako Island is once again at risk.