In a post-apocalyptic world scarred by monsters and societal collapse, a stoic wanderer named Agrippa rescues a young woman named Claudia from bandits and a monstrous dog near the isolated settlement of Mist. Reluctantly, Agrippa accompanies Claudia back to Mist, only to witness it be devastated by a massive, slug-like creature known as a loimos. The monster infects the settlement with a deadly green miasma, leaving survivors doomed without a cure.

In the aftermath, a young man named Remus—idealistic and desperate to prove himself—volunteers to journey north in search of the fabled Celestial City 66, a legendary sanctuary rumored to hold the technology to cure any disease. He is joined by Agrippa with precious silver as payment and Claudia, who refuses to let Remus go alone. Together, the trio sets off across dangerous terrain, haunted forests, and the remnants of a lost world, while facing grotesque creatures and uncovering uncomfortable truths about faith, survival, and human history.

As the group travels, tensions flare and bonds are tested. Agrippa reveals a haunted past and superior survival skills, while Claudia and Remus, both inexperienced but determined, struggle to hold onto hope. The story weaves faith-based lore with horror, dystopian decay, and coming-of-age grit—leading toward the perilous mystery of whether the Celestial City 66 even exists, and what awaits them if it does.