In a society determined to keep her under lock and key, Tavia must hide her siren powers. Meanwhile, Effie is fighting her own family struggles, pitted against literal demons from her past. Together, these best friends must navigate through the perils of high school's junior year. But everything changes in the aftermath of a siren murder trial that rocks the nation, and Tavia accidentally lets out her magical voice at the worst possible moment. Soon, nothing in Portland, Oregon, seems safe. To save themselves from drowning, it's only Tavia and Effie's unbreakable sisterhood that proves to be the strongest magic of all.