The series follows master negotiator Kōjirō Shindō, working for the Ministry of Foreign Affairs, as he chooses to represent Yaha-kui zaShunina, an otherworldly entity with the main intention to advance the world by progressively introducing four mysterious devices to humanity.

Mado Nozaki wrote the series, with Kazuya Murata directing the anime, and illustrator Ako Arisaka doing the original character designs.

[1] The anime aired from April to June 2017, on Tokyo MX, MBS, BS Fuji, and AT-X with online streaming via Amazon Prime Video[2] M.A.O performed the opening theme "Tabiuta" (旅詩, transl.

Kado - The Right Answer: Blue Spring and Railgun) was launched on North Star Pictures' Web Comic Zenyon website on April 29, 2017.

The story takes place after episode 5 and follows a group of high school students whose lives are radically changed with the arrival of Kado and the infinite energy source, Wam.