Oosawa Maria is a Japanese photographer currently working in Shanghai, China. Along with her partner Mino, she searches for potential newsworthy stories throughout the city. When strange events occur at a local festival, Maria and Mino immediately investigate. Quickly, the two are immersed in a battle between unknown masked men and a strange, white-haired woman. Just when Maria is about to be caught in the crossfire, an old friend by the name of Canaan appears and helps Maria escape. But a sinister plot over a deadly virus soon develops, and Canaan learns she must confront her past if she wants any chance at stopping the perpetrator and saving her friends. [Written by MAL Rewrite]

Canaan is the sequel to the Canaan scenario created by Kinoko Nasu and Takashi Takeuchi that is unlocked in the visual novel video game 428: Shibuya Scramble. The scenario features Canaan, Alphard Alshaya, and Maria Oosawa, and takes place 2 years before 428: Shibuya Scramble while the anime takes place 2 years after.