The military facility goes on high alert; Chris manages to escape, but is not the only one who gets out.
Bristol Cove mourns a loss, causing Ryn to experience a new human emotion.
When Ben and Maddie attend his mother's fundraising gala, an unexpected guest shows up and offers to put an end to the overfishing that threatens the lives of the mermaids in Bristol Cove.
Those searching for Emma receive help from unexpected allies; Emma struggles to resist her dark urges as she tries to find Merlin before her transformation is complete.
Regina steps up in an unexpected way to protect Emma; a celebration at Camelot turns deadly; Hook tries to bring Emma back to the light.