Eager to know why her best friend’s boyfriend dumped her for a man, the headstrong Eiya Arakawa suggests a meeting with them. Gathered together at a café, Yuuga Oota agrees to answer Eiya’s questions only if she can correctly ascertain the relationship of a couple sitting across from them, which she does on her first attempt. Amazed by her astounding intellect and intuition, he invites her to a private meeting where he introduces her to the concept of Slave Control Method, or SCM, a retainer-like device that has the ability to turn people into slaves. When two SCM users enter a duel, the devices exert a powerful influence on their brains. Once the duel is over, the SCM amplifies the loser’s sense of obligation and forces them to bend to the will of the winner. Wanting desperately to test his own abilities, Yuuga asks Eiya to act as his insurance in the event that he himself becomes a slave. Granted access to 10 million yen, Eiya’s job is to convince Yuuga’s would-be master to free him from his servitude. Though hesitant at first, Yuuga’s words resonate with her personal yearning for something more from her life, and she agrees to his request. However, when a mysterious organization begins rapidly accruing slaves, Eiya becomes entangled in a game far more dangerous than she ever could have imagined. [Written by MAL Rewrite]

Virtual Reality and the arrival of Circlet Technology has changed people's lives. A new competitive electronic sport called Circlet Bout emerges, and schools duel to determine the strongest Circlet Bout Club and player. One day, Yuuka Sasaki gets mistaken for a challenger and battles against Chikage Fujimura, the best player in Japan, tying the intense fight despite her inexperience. These events lead to her passion for the sport, deciding to become a Circlet Bout player. Two years later, Yuuka moves to Tokyo and enrolls in Union School, a place where she can practice and pursue her dream of fighting Chikage again. After her arrival at the Union School, she discovers the club closed. Now her first goal is to help the athletic Miyuki Kasahara and club manager Ayumu Aizawa reopen Union's Circle Bout Club and return it to its former glory.

Okano Makoto transferred to the school in his home town. There, he spent normal but happy school days with his sister, Hinata, a jokey classmate, Tachibana Tsutomu, Shikouin Kasumi, Tsutomu's childhood friend, and other friends. One day, after school, Makoto heard someone playing the harmonica. That melody made him feel something old, and it brought him to the roof of the school buildings. There, he met a girl in the dusk. It was Narukaze Minamo who turned her face to him with a smile. She was a childhood friend, but they had lived separately for years. Hiding their true thoughts, Makoto and his friends spend their lives in school. Their stories in a mysterious town are about to begin.

Kou comes to a slum neighborhood in search of his elder brother Takumi and finds him to have become the head of a private detective firm. Kou is drafted by Takumi to do errands and chores in the detective firm, and they come to meet various interesting people... (Source: MAL News)