Kaoru Kunou, a former legend known as the "Dungeon Maniac," is now, for certain reasons, a bottom-tier explorer. Though worn out by reality, he continues to chase the fleeting dreams and youth of his past. One day, by chance, he saves S-class gal streamer Shion from a crisis, and she falls for him at first sight. Initially flustered by Shion’s overwhelmingly bright and charming advances, Kaoru gradually finds himself healed and drawn to her. Eventually, the two form a temporary mentor-student duo and set out to challenge the depths of a dungeon tied to their pasts, but what lies ahead!?

A thick mist covers the city of Faith-Delhi constantly. In the mist and smoke of this metropolis, demons known as "Pagans" lurk in the shadows. Pagans are born when humans fail to join the other souls in the path to reincarnation. There is a group known as the "Twanbach Funeral Service Company" who specializes in hunting these Pagans. Reginald, a 100+ year old vampire that looks like he's 20 years old, gets hired by the Twanbach company by the mysterious twins, Vanessa and Veronica Twanbach.

Yuma Saihashi is a miko who lives at the shrine. She is a lone wolf who distances herself from others and refrains from making friends. During her free time, she gives massages to the elders in the neighborhood but refuses their gifts. Like her friend Chinami, she can emit electromagnetic waves. Her power is not as strong as Chinami's but she can control it better. Spin-off of the CODE-E Anime.