Hayato is a street child who races through the city every day to earn money for his younger sister Himari's medical expenses while she remains hospitalized. One day, he encounters a mysterious boy painting graffiti on a rooftop. The appearance of this stranger coincides with the sudden emergence of a gigantic ayakashi, a supernatural creature from Japanese folklore.

The ayakashi charges toward the hospital where Himari is a patient, revealing that the creature's target is Hayato's sister. With no other options, Hayato is forced into a fight for survival, combining parkour-style urban acrobatics with ayakashi combat to protect both his sibling and the city he calls home. The battle draws Hayato into a larger struggle between modern ninja and supernatural forces operating beneath Tokyo's surface.

The story is set against the backdrop of Tokyo, with the city's streets, rooftops, and buildings serving as the arena for stylish action sequences. The narrative follows Hayato as he discovers his own capabilities and the hidden world of ayakashi that exists alongside everyday urban life. His primary motivation throughout remains the protection of his beloved sister Himari, whose hospitalization and subsequent kidnapping drive the conflict.

Written and illustrated by Shuusaku Namikawa, the series was published in Kodansha's Monthly Shonen Magazine beginning in March 2025. The manga was released across two volumes containing nine chapters before the author announced its discontinuation on Twitter on October 21, 2025, with no reason provided for the series ending prior to the planned final chapter's release.