Journey to where the fog never lifts… Libelle, a city by the sea. Those who venture into its fog are said never to make it back alive—a murderous phenomenon that’s another of the Four Major Human Errors that has ravaged the world. But for Menou, it just may be the solution she’s looking for. To fulfill her role as Executioner, she needs to find a way to murder Akari, the girl who seems to spring back to life whenever she’s killed. Maybe this time, Menou will be successful in carrying out her duty... but a calculated encounter with Manon, the daughter of Count Libelle, shifts all their fates in a direction that even Akari never could have predicted. Just what will become of the Executioner and her seemingly unkillable target...?

The Lost Ones are wanderers who come here from a distant world known as "Japan." No one knows how or why they leave their homes. The only thing that is certain is that they bring disaster and calamity. The duty of exterminating them without remorse falls to Menou, a young Executioner. When she meets Akari, it seems like just another job...until she discovers it's impossible to kill this girl! And when Menou begins to search for a way to defeat this immortality, Akari is more than happy to tag along! So begins a journey that will change Menou forever...

Pandmonium in the mountains. Hoping to avoid a future where Menou dies trying to save Akari, the girl from Japan runs away with her sworn enemy, Momo. The pair ride the rails to a secluded village in the mountains where they believe they’ll be safe for a few days. Unfortunately, they’re not the only ones who decided to stop off there. Manon and Pandmonium have arrived as well, and they aren’t alone. Akari had hoped keeping away from Menou would be enough to spare the girl she holds dear, but keeping the Executioner alive may require a more drastic course of action...

To kill Akari, Menou scours the outer reaches of the West in search of a legendary blade that turns all it touches into salt. There, she stumbles across Sahara, a monk, who has history with the young Executioner and begs her to take her life for reasons unknown. Meanwhile, one of the Four Major Human Errors begins to unfold in the undeveloped regions of the East and slowly inches toward them, leaving a trail of destruction in its wake...

On the train to Garm, the ancient capital where Akari is to be sent home, a terrorist attack and a foe conjured via taboo magic block her and Menou’s path. And if that wasn’t bad enough, the train is sent careening out of control, headed for an inevitable collision! The only way to stop the impending disaster is for Menou and Akari— Executioner and her Otherworlder target—to join forces. But as Menou will soon learn, this is only the beginning of a sinister plot centered around them...

Once upon a time, in the not too distant past, a holy maiden was summoned. Not just any holy maiden—one hailing from modern Japan. But this story is not her story. This is the tale of the humble accountant, Kondou, who accompanied her and his trials and woes as he accounts in a new world... But no tale is complete without a love interest. And who better to play that role than the handsome knight captain Aresh? Will he begin a personal quest to save said bean counter—who toils around the clock—or is Kondou doomed to be married to his work evermore...?!

The Lost Ones are strangers from another world, hailing from a place no one has ever heard of called “Japan.” These wanderers have been associated with catastrophes since many years ago and the solemn duty of exterminating them without remorse falls to Menou, a young Executioner. But when her mission is complicated by a Japanese girl named Akari who refuses to die, Menou embarks on a peculiar journey to find something that can slay even an immortal who insists on traveling with her would-be-killer!