Kaoru was suffering from xeroderma pigmentosum (XP), an illness, which also might be described as the allergy to the sun, and was not allowed to be exposed to sunlight. The only motivation in her life was singing, which also was the only connection to the outside world.One day, an incident drastically changes her life. Kaoru returns home at 4:00 am, before sunrise. Outside her room window, she spots a high school student standing with a surf board in his hands. It becomes her routine to watch him and his friends come and go to the ocean every morning, before going to sleep. Their destined encounter takes place during the few hours before the break of day, drawing together two individuals that would have never met in daylight.