The use of augmented reality has become an integral part of daily life in the upcoming years. Yasako Okonogi, a soft-spoken middle school student, and her family have recently relocated to Daikoku City despite rumors of residents vanishing mysteriously. Her grandmother, affectionately known as "Mega-baa," operates Megasia, an establishment that deals in illicit tools that can connect with aspects of the virtual world. Interestingly, Mega-baa also manages an unlicensed investigative agency known as "Coil" that consists of Yasako's peers. These children are tasked with identifying and rectifying virtual world infections. When Yasako's pet cyberdog, Densuke, becomes entrapped while pursuing a puzzling virus, Fumie Hashimoto, a fun-loving Coil member, rescues it and brings Yasako into the team's fold. Meanwhile, an unpleasant hacker, Yuuko Amasawa, often referred to as Isako, is also tracking these same virtual malady and anomalies. Will Coil be able to uncover the truth about these enigmatic viruses and system breaches, and if so, what will it cost them?