Siren

Donna and Ryn clash over their feelings about humans. Xander, Chris and Decker race to capture their own mermaid.

Ben and Xander abscond with the North Star to catch their own mermaid but things don't go as planned.

Bristol Cove mourns a loss causing Ryn to become more human and showing the distance between Ben and his father.

Donna returns but her "companions" have different plans than she does. Ben, Maddie and Dale work together to try and stop Bristol Cove's newest threats.

The enchanting siren song takes hold of Ben and Decker while Dale must answer for the escalating crime in Bristol Cove. Xander's past transgressions drive a wedge between him and Calvin.

A new environmental threat wreaks havoc on Bristol Cove's shores, bringing more mermaids to land and more threat of discovery. Ben continues to struggle with the effects of the siren song. Maddie's mom returns to town and Ryn attempts to adapt to life on land.

Ben and Maddie work with Ryn to try and keep the pack hidden from the rest of town, but the new mermaid's quick degradation on land forces a ticking clock as they figure out how to get them back to sea.

Ryn fights to maintain leadership of the pack when her loyalties are questioned over her friendship with Ben and Maddie. Ben interferes in a mermaid ritual and Helen discovers more about her family lineage. Maddie comes up with a solution to study the siren song and its affects.

Ryn decides they need to find another solution for housing mermaids as the pack dynamics remain precarious. Ben becomes a mentor to Levi as he tries to learn how men behave on land and Maddie continues to struggle with her mother's renewed presence in her life. Xander utilizes some new leverage to try and locate Levi.

Ryn continues to try to teach the other mermaids to be more human on land in order to better integrate, but some are starting to resist her. Maddie finds herself in a dangerous situation trying to help her mom, who has fallen off the wagon. Ben and Xander work to reconcile in order to work together and get the mermaid pack back into the water.

Katrina continues to try and get the rest of the mermaid pack on her side. Ben, Maddie, and Helen try to help Ryn maintain control and try to come up with a strategy to stop the oil company’s offshore plans.