What if there was something sinister swimming beneath the sea's surface? In Freeform's next epic tale, "Siren," the coastal town of Bristol Cove, known for its legend of once being home to mermaids, is turned upside down when a mysterious girl (Eline Powell) appears and begins wreaking havoc upon the small fishing town. Using their resources, marine biologists Ben (Alex Roe) and Maddie (Fola Evans-Akingbola) must work together to find out who and what drove this primal hunter of the deep sea to land, and are there more like her out there?