A young man writes a novel about his forbidden love with his sister, who works overtime in the office on a holiday. Based on the manga of the same name by Naoki Yamamoto, and covering the manga's inspiration source, Juro Kara's "Anjuko's Shoes" and Ogai Mori's "Sansho Dayu".
After attending the funeral of Yu, a childhood friend, Toru gets drunk and misses the last train home. He saves a girl, Nao, after hearing her jump into the river, and finds that she was also a friend of Yu. Together, they wander the streets until morning.
