K-20: Legend of the Mask (K-20: Kaijin nijû mensô den) (2008)

K-20: Legend of the Mask is set in the fictional Japanese capital of Teito, in 1949. World War II has been avoided. The system of "nobility" established in the Meiji Era (mid-late 19th century) continues today, creating an extreme divide between the upper and lower classes. Ninety percent of the country's wealth is controlled by upper members of society.

Teito had been gripped by the emergence of a phantom thief who steals priceless objects from the rich. He is known as "The Fiend (Kaijin) With Twenty Faces" or simply "K-20".

The protagonist of the story is Heikichi Endo, a circus acrobat who is deceived by K-20 and set up to take the fall for the phantom thief. Using his incredible physical dexterity, Heikichi wages war against K-20. He fights alongside K-20's next wealthy target, Duchess Yoko Hashiba, and her husband-to-be, brilliant detective Kogoro Akechi. But what is the ultimate decision Heikichi has to make?