Mia (Luna Wedler) is a 15-year-old girl on the cusp of becoming something completely different. Whereas most teen girls hit adolescence and grow into women, Mia finds herself craving fish and growing gills. Soon, her toes start to fuse together and her legs become bruised. For a curious teen, this transformation is troubling, and Mia demands answers out of her mother (whom she can't recall ever seeing pregnant in photos). Mia starts to suspect maybe she comes from something otherworldly and her affinity for the water might be more than just a desire to swim. Perhaps it is her true home.