Heavenly Delusion (Tengoku Daimakyou) Episode 3 is primarily a flashback and takes us to Asakusa, Tokyo, in the year 2034—ten years after the Great Collapse and five years before the main timeline of the series. We follow the story of the siblings Takehaya Haruki and Kiruko as they navigate a post-apocalyptic world while confronting dangerous creatures known as the "Man-Eaters." In this episode, we also meet "The Doc" and Inazaki Robin, two figures who play significant roles in the siblings' lives.

The pivotal moment of the episode occurs when Haruki, in an attempt to protect his sister, is severely injured by a Man-Eater. He appears to die, only to later awaken in Kiruko's body. This development leaves both the characters and the viewers questioning the nature of Haruki's survival and his connection to Kiruko. The disappearance of The Doc and Robin adds to this mystery, leaving us with more questions than answers.

While Haruki had five years to process the bizarre circumstances, Maru must now grapple with the revelation that his newfound soulmate is not who he originally believed her to be. As the characters try to make sense of their situation, a new threat emerges in the form of a giant Man-Eater, forcing them to confront the immediate danger.