Grandmother and granddaughter head to a seaside amusement park. Eager to grab a limited-time free toy, grandma breaks her promise and leaves her young granddaughter all alone on a tour boat. Due to damaged amusement facilities, the small boat drifts toward the open sea, leaving the child alone in deep peril. The mother keenly senses the abnormality, rushes to the scene disregarding family pressure, and coordinates fully with her husband to launch a search and rescue. Although the child is safely rescued, her inner self is left with an indelible psychological trauma. Afterwards, grandma refuses to admit her mistake, shifts the blame in various ways, and tries to use her elder status to bypass the rules and approach the child. The couple withstands family public opinion, separates the park's responsibility from individual liability, and establishes boundaries for getting along.