This film is about an alcoholic birth mother and a psychiatrist stepmother who are trapped in a forest cabin in Jeju, Korea, during a typhoon. They spend a day together, hiding their true identities from each other.

Gosari Monsoon refers to the spring showers unique to Jeju Island. It is named after the image of fern shoots, which push through the once-frozen winter soil, standing tall as they greet the spring rains.