In an effort to save Hope, Ryn and Ben confront Tia in an undersea battle between the mermaid tribes. Maddie and Robb work to find a cure for Xander, while Helen and the hybrids help restore order. Ted struggles to accept Ben's reality. Season finale.
Season Number: 3
Episode Number: 10
Episode Title: The Toll of the Sea
Air Date: May 28, 2020