Midnight Running (2006)

Kaoru has Xeroderma Pigmentosum (XP), and is not allowed to be exposed to sunlight. She sleeps during the day and is active at night. She busks every night in front of a station playing guitar. Outside her bedroom window, she spots a high school boy with a surfboard. She watches him and his friends visit the ocean every morning, before going to sleep. One day, she introduces herself to him without letting him know about her illness. He is Kji Fujishiro (Takashi Tsukamoto) When her cousin drags her home, they sit by her window while they watch Kji meet his friends. Kaoru explains everything, and her cousin notes that she probably goes to the same school as him, and offers to spy on him for her.