Elite plastic surgeon Do Jiui has his perfect life turned upside down when he's unexpectedly sent to the remote island of Pyeondongdo as a public health doctor. Surrounded by the sea, the island is more than just isolation for him, as past trauma has turned the ocean into an unknowable terror and a massive prison. Intrusive locals and grotesque bugs turn life into a living hell for the city man. Amid it all, a mysterious nurse, Yuk Hari, appears. Hiding secrets behind her gentle smile, she always seems to be nearby when Jiui is overwhelmed by his fear of the sea. As the two become entangled on the small island, can Jiui overcome his past and escape safely?