The Mizuhanome System is a highly advanced development that allows people to enter one of the most intriguing places in existence—the human mind. Through the use of so-called "cognition particles" left behind at a crime scene by the perpetrator, detectives from the specialized police squad Kura can manifest a criminal's unconscious mind as a bizarre stream of thoughts in a virtual world. Their task is to explore this psychological plane, called an "id well," to reveal the identity of the culprit. Not just anyone can enter the id wells; the prerequisite is that you must have killed someone yourself. Such is the case for former detective Akihito Narihisago, who is known as "Sakaido" inside the id wells. Once a respected member of the police, tragedy struck, and he soon found himself on the other side of the law. Nevertheless, Narihisago continues to assist Kura in confinement. While his prodigious detective skills still prove useful toward investigations, Narihisago discovers that not everything is as it seems, as behind the seemingly standalone series of murder cases lurks a much more sinister truth. [Written by MAL Rewrite]

Through their tutor Fuutarou Uesugi's diligent guidance, the Nakano quintuplets' academic performance shows signs of improvement, even if their path to graduation is still rocky. However, as they continue to cause various situations that delay any actual tutoring, Fuutarou becomes increasingly involved with their personal lives, further complicating their relationship with each other. On another note, Fuutarou slowly begins to realize the existence of a possible connection between him and the past he believes to have shared with one of the five girls. With everyone's feelings beginning to develop and overlap, will they be able to keep their bond strictly to that of a teacher and his students—or will it mature into something else entirely? [Written by MAL Rewrite]

Miu Takigawa views the world from behind the safety of her bangs, content with peacefully passing unnoticed through life. Reserved and timid, Miu struggles to converse with or even smile at customers when at her part time job, but she works tirelessly to support her mother and precious little sister, Haru. It is a shock when a letter arrives from the entertainment company GIP, announcing that she has been chosen as a candidate for their new project. Miu decides to accept the invitation and heads to the meeting spot where the eccentric ensemble of other candidates filter in, all summoned by their own letters. Not long after, the girls are escorted by a manager to a luxurious secret facility, where it is explained that they must follow the mysterious directions of "The Wall," whose orders are absolute. The 24th of December, 2016, will see the birth of idols like no other; on that day, the group 22/7 will debut, whether or not Miu and the other members are ready to take the stage. [Written by MAL Rewrite]

Itsuki Hashima is a light novelist obsessed with little sisters, strictly focusing on them when he writes his stories. Despite his personality, he is surrounded by a tight circle of friends: Nayuta Kani, a genius yet perverted novelist who is in love with him; Haruto Fuwa, a fellow male author whose work has seen considerable success; Miyako Shirakawa, a good friend that he met in college; and Chihiro, his perfect younger step-brother who takes care of the housework and cooking. Together, they play strange games, go on spontaneous journeys, crack silly jokes, and celebrate each other's successes. However, each individual must also deal with their own issues, whether it is struggling to meet a deadline or coming to terms with traumatic events buried in their past. [Written by MAL Rewrite]