@TV Promos Prodigal Son stars Tom Payne, Michael Sheen, Bellamy Young, Halston Sage, Aurora Perrineau and Lou Diamond Phillips, and premieres September 23 on Fox.
Mermaid mating season has begun, with Ryn knowing she will need to go back to the sea to help her colony. The hybrids convince one of the sirene to come with them to a remote location, leading Helen and Ben on a hunt to find them.
