Wedding planner Callie returns home to Lucky Harbor, where an encounter with her still sexy high school crush, Tanner, who has recently been reunited with his teenage son, makes her rethink her decision to remain single.

Dayeon wants to be a haenyeo just like Grandma. The haenyeo dive to pluck treasures from the sea. To Dayeon, the haenyeo are as strong and graceful as mermaids. Dayeon practices holding her breath while they do the dishes. And when Grandma suits up for her next dive, Dayeon grabs her suit, flippers, and goggles. Scary thoughts of the sea keep Dayeon clinging to the shore, but with Grandma's guidance, Dayeon comes to appreciate the ocean's many gifts....