Since ancient times, the citizens of Slantania have lived within a shroud of miasma, a force that brings forth monsters creating havoc around the world. When the kingdom's Order of Knights becomes incapable of containing the monsters, the Grand Magus summons a holy maiden—the legendary Saint—to obliterate the horrid creatures and restore peace. One evening, as Sei Takanashi returns home from a long day at work, a magical force pulls her into a foreign world. Upon her arrival to the kingdom of Slantania, she overhears that the Grand Magus inadvertently summoned two Saints—Sei and a brown-haired girl. Needing only one holy maiden, the prince declares the other girl as the Saint, leaving Sei to her own devices. Sei sets her sight on the Medicinal Flora Research Institute, an establishment known for its studies regarding herbs and potions. While indulging in her latest passion, Sei has a fateful encounter with the commander of the Third Order of Knights. But little does she know, her aptitude as a Saint will continue to exert its influence over her new life.

After preventing Japan's destruction, Akira Takizawa made one final request to become the King of Japan, before he erased his memories once again and disappeared. Leaving Saki Morimi with his cellphone, the only clue she has in regards to Akira's whereabouts is the message, I'll be waiting where our journey started. Six months later, rumors have spread about Akira, and Saki's search leads her to New York City. However, Saki is not the only person who goes to investigate—with several billion yen burning a hole in their pockets and a challenge to save Japan, the remaining Seleção are not far behind. Some are willing to help Akira achieve his goals, but a few are making dangerous moves in order to eliminate him and achieve their own picture of a better Japan. With rising stakes and new revelations, the game is still on.

Kino, a 15-year-old traveler, forms a bond with Hermes, a talking motorcycle. Together, they wander the lands and venture through various countries and places, despite having no clear idea of what to expect. After all, life is a journey filled with the unknown. Throughout their journeys, they encounter different kinds of customs, from the morally gray to tragic and fascinating. They also meet many people: some who live to work, some who live to make others happy, and some who live to chase their dreams. Thus, in every country they visit, there is always something to learn from the way people carry out their lives. It is not up to Kino or Hermes to decide whether these asserted values are wrong or right, as they merely assume the roles of observers within this small world. They do not attempt to change or influence the places they visit, despite how absurd these values would appear. That's because in one way or another, they believe things are fine as they are, and that the world is not beautiful; therefore, it is.

Gesicht, an android police detective of Europol, is tasked with finding the murderer of Montblanc, a retired war hero robot. Although it appears that only a robot could have committed this crime, the murder of a renowned robot rights activist casts doubts on the criminal's identity. Indeed, outside of an isolated and unexplained incident that occurred eight years ago, robots are programmed to be unable to kill human beings. However, the lack of human evidence on the crime scene and the similarity of modus operandi lead Gesicht to suspect that the two murderers might be the same being—be they man or robot. Shortly after Montblanc's passing, another retired elite war robot is mysteriously eliminated. Gesicht notices a pattern in the choice of murder victim: both dead robots belonged to a group of the seven most powerful war machines ever designed. Determined to stop the murderer from eliminating the five remaining veterans, Gesicht seeks help from Atom, a cutting-edge android who resembles a human boy. The duo must now hunt down the rogue killer before the series of murders is carried on, lest the very fabric of society suffer irremediable damage.