Two years ago, Shibuya was ravaged by a biological terrorist attack using the deadly Ua virus. Oosawa Maria was saved when her father inoculated her against the virus, but is left with partial amnesia from the shock. Now working as a camerawoman, she reunited with her friend Canaan in Hong Kong. Canaan, an assassin gifted with Synesthesia, is being targeted by the terrorist squad Snake. Meanwhile, numerous groups converge on Hong Kong, all after either Canaan or Maria.