In a society where everyone changes day and night to adapt to a new climate catastrophe characterized by extreme ultraviolet rays, Inkyung, who lives with her older sister at work, works part-time as a home insurance advisor during the day when everyone else is asleep.
No matter how many times she changes TV channels, In-Kyung, in the middle of the day, working on a boring broadcast that only shows people going out, gets a call from her sister, who she thought was sleeping in her room. She searches for her sister at home, but in her small two-bedroom villa, her sister is nowhere to be seen. When the bewildered In-Kyung cannot resist her sister's insistence, she grabs her protective suit and prepares to leave her house, when suddenly a strange older sister appears in her house.
Unlike her sister on phone calls, she convinces In-Kyung to stay at home. Feeling alienated by her older sister's attitude, In-Kyung, who fled the noontime outdoors with her naked body, no longer stays in the shade, but opts to go out into direct sunlight, whatever the outcome.