No one has entered Gecko Moria's garden for a decade. A great wall blocks the way, and terrifying shadows are poised to attack any intruder. One day, a child named Perona notices a gap in the wall. She crawls through, beckoned by the secrets on the other side.

When Sakiko Mizushima needs a hero the most, she is ignored, and left an orphan. An investigation is launched, but no evidence is found to charge the hero who abandoned her family. Living in despair, Sakiko's soul cries out for justice. When the infamous 'Hero Killer' murders a pro hero in her ward, Sakiko cannot suppress her vengeful heart any longer.