In a world powered by advanced technology, crime and action sweep through the archipelagic nation of cremona. Chief among the major players is “Killer B” - a serial killer who has thrown the city into chaos. The stories of Koku, the protagonist, Keith, a legendary investigator of the Royal Investigation Service, and a mysterious criminal organization intertwine on the path to reach their objectives. A wide variety of unforgettable characters surround them on the journey, as they attempt to stop a chain of horrific crimes in this suspense drama.

In the first season of B: The Beginning, two men confronted their own past with great sacrifice. Maverick detective Keith Flick fought against his demons and finally exposed the dark secrets behind the Kingdom of Cremona. Mutant wunderkind Koku finally reunited with the most precious memory from his stolen childhood. Several months have passed since then, and the entire world seems to have forgotten the turmoil caused by those events. As Keith returns to the Royal Police to conduct his own investigation, Koku and Yuna try to enjoy an ordinary life in peace. But the consequences of the Jaula Blanca experiments are far from being extinct, as Koku soon discovers when his supposedly dead lab mate Kirisame suddenly shows up.