Ben and crew of The North Star uncover a device emitting a strange sound. Meanwhile, Ryn finds shelter in the home of the local folklore expert.

When Ryn is taken in for questioning, Maddie rushes to her rescue. Meanwhile, Ben and Xander return to the deep sea to search for answers, only to be met by an uninvited guest.

In the season finale, the enchanting siren song takes hold of Ben and Decker. Meanwhile, Dale must answer for the escalating crime in Bristol Cove.