Since ancient times, the ninja and the yakuza have been at war, spilling blood around the world as empires rise and fall. So when, in the modern age, Shinoha, a ninja, meets Kiwami, a gangster following the path of the yakuza—the gokudo—and discovers they have common interests, the obvious assumption is that nothing good can come of it. But can it be that one burgeoning bromance will shake up a 300-year grudge? Who will win the struggle for real ultimate power?

Once upon a time, there was a girl named Sora. She loved to sing, but one day, something happened that made her scared to sing in front of others. As days passed, she forgot how to sing, and even how to laugh. Then, one day, she and her little brother Daichi stumbled upon a mysterious pond.

Alma, an autonomous self-learning robot with advanced combat capabilities, was created by two genius scientists, Enji Kamisato and Suzume Yobane, who developed Alma's artificial intelligence and robotics, respectively. After being mocked by their former acquaintances, the duo have worked together in order to show the world their true talents. But even though they cooperate in their work, the two scientists cannot seem to get along in their personal lives. However, despite their constant bickering, Enji and Suzume develop a glint of mutual affection—feelings that do not go unnoticed by their adorable robotic creation. Now curious, Alma starts to question the true nature of her creators' relationship. As she learns more about humanity from those around her, Alma's bonds with Enji and Suzume only grow stronger.

It is the Edo period. Ichitarou, the young master of Nagasakiya, one of the largest stores in Nihonbashi, has been in poor health since birth and is unable to go out. However, Ichitarou is always protected by demons such as Shirasawa and Inugami, who serve him. One night, Ichitarou goes out secretly and witnesses a murder. From that day on, bizarre murders begin to occur one after another in Edo... With the help of the demons, Ichitarou's search for the culprit begins!