In response to the worsening crime rate, Japan creates Tokyo Butei High, an elite academy where "Butei" or armed detectives hone their deadly skills in hopes of becoming mercenary-like agents of justice. One particular Butei is Kinji Tooyama, an anti-social and curt sophomore dropout who was once a student of the combat-centric Assault Division. Kinji now lives a life of leisure studying logistics in order to cover up his powerful but embarrassing special ability. However, his peaceful days soon come to an end when he becomes the target of the infamous "Butei Killer," and runs into an emotional hurricane and outspoken prodigy of the highest rank, Aria Holmes Kanzaki, who saves Kinji's life and demands that he become her partner after seeing what he is truly capable of.

Any network runs all over the world, and the development of the information network reaches its acme. In this age, there are two developed worlds; "the real world" and "wired", or the virtual network world. Soma Toru belongs to a hacking group, Steppen Wolf, which runs around the network world freely. They attack the database of the UN forces as their last work. During this attack, he loses Nonomura Yuya, his friend as well as the team leader. Toru is arrested by the army. In exchange for letting him free, he has to work for an anti-hacker organization, the first squad of the UN Security Force Information Administration Bureau. Working for them, he is looking for the person who killed his friend, while the other members also have their own reason to fight. The three-way fights of the terrorist group, the security enterprise, and the army, continue every day. The various events occurred during the fight seem to be independent of each other at the first glance, but they're converging on one event as if they were attracted by something. Based on the game by GIGA. (Source: ANN)

"Logic" is the concept that governs emotions, abilities, ideals, memories, and all other abstract properties that make up life in various worlds. With its power, however, alien "Foreigners" are able to pass through portals imbued with their respective world's Logic and pose a threat to other worlds. To counter this problem, the Another Logic Counter Agency (ALCA) from the human world of Septpia employs "Logicalists," people with the power to form bonds with the Foreigners who seek peace and share their Logic, tasked with dealing with all possible dangers. After overloading his powers two years prior, Yoshichika Tsurugi has lost the ability to use Logic in combat, making him no different from a regular citizen. However, his life soon returns to the battlefield when he meets Athena, a Foreigner goddess from the world of Tetra-Heaven. She brings Yoshichika his missing Logic Card, allowing him to become a Logicalist once again. Soon after, Yoshichika forms a contract with Athena and joins ALCA. There, he meets other Logicalists, and only by working with them can he hope to bring an end to the threats once and for all. [Written by MAL Rewrite]

It’s been 7 years since Yuuichi Aizawa visited his aunt Akiko, but now that his parents have gone to Africa to pursue their careers, he is finally back in the little northern town. Yuuichi is not really overjoyed with the prospect of living here though, because all of his memories of this place and the people living in it have mysteriously vanished. His cute cousin Nayuki seems like a stranger as well, even though he used to play with her all the time when they were younger. On the day of moving into his new home, Yuuichi starts unpacking the boxes and stumbles upon a red headband that no one seems to recognize. This is one of the first clues that will make Yuuichi take a stroll through the snow-covered town and make him start recalling fragments of his past, broken promises and buried secrets. Yuuichi soon realizes that there is something supernatural going on, and all of his new female acquaintances seem to have links to his forgotten past.