Based on the popular Japanese TV series about a young high school delinquent recruited by a special police force unit investigating juvenile crimes. Her unique M.O. was her weapon of choice — a solid steel yo-yo that she wielded with deadly accuracy.

Saki Asamiya is now retired from the past and trying to graduate high school in order to lead a normal life. But when she uncovers an evil terrorist group brainwashing teenagers at a private reform school, she enlists herself back into the action. With the help of her friends and a brand new ultra deadly yo-yo, she resolves to take on the terrorists. But has her retirement made her too soft? Does she still have what it takes to be a deadly secret agent, or has she become just another average little schoolgirl?