Sisterhood portrays a current reality in Japan, showing the vision and lives of different people, such as a nude model, a music artist, a student and other diverse individuals who give their opinions in front of the camera.
Kaori (Nori Sato) runs a small piano studio. One of her students is Yuu (Uwa Ishibashi). On the way from a recital, Kaori is sexually assaulted by Yuu's father (Kentaro Furuyama). Kaori later learns Yuu has also been sexually abused by her father. Kaori and Yuu share each other's pain and eventually Kaori decides to fulfill Yuu's wish.
An Orthodox priest, Father Nikolay, the brother of a Yakuza boss, is drawn into in a mob war in Japan. He escapes to the small Russian village of Glubokoe, where he finds that war has found him again.
After their class reunion, Yukari, Kiriko, and Niko launch a website for punishing people who have done wrong, yet escape law enforcement. As their website goes viral, Kiriko and Niko's acts of violence increase in intensity to satisfy their need for attention and the demands of their growing subscribers.
The urban legend about the blog which brings tragedy and fear. Shy and inner minded high schoolgirl Hitomi starts her blog with fake name. She writes and jokes about her school and friends, but whoever name is written on the blog encounters terrifying tragedy, even death.