In a world where memories exist in memory chips separate from the body, death of the body no longer means death of the soul. It is possible for memories to be viewed, altered, and transferred between bodies. These memory chips are used by the rich to obtain eternal lives in carefully selected bodies, while for the poor, selling their own bodies and conserving their souls in the chips often become the only way to earn a living. An electrolytic cloud in the sky serves as a barrier between the heavens of the fortunate and the underworld of the destitute, making this social division impregnable. One day, a man named Kaiba wakes up in an empty room with no memories, a mysterious hole in his chest, and a locket holding the picture of an unknown woman. After escaping an attack and stumbling upon a decrepit village of underworld residents, he begins his adventure across the different planets of this strange universe to find out more about his own identity and the woman he once knew. Through a journey of self-discovery and acceptance, Kaiba weaves together tales of souls and spirits and explores the importance of memories.

Vampires—supernatural beings that feed on the life essence of the unsuspecting at night—have been around for centuries. However, high schooler Karin Maaka is unusual, even among her own kind. Unlike her vampire family, ever since she was a child, Karin has suffered from polycythemia: a rare disorder which causes her to periodically produce excessive amounts of blood. And the more blood she produces, the more anemic and lightheaded she gets, ultimately leading to frequent nosebleeds. Her only solution? Force her excess blood onto random strangers, which surprisingly causes these victims to become livelier and happier than before. With her siblings—Anju, her reserved yet affectionate younger sister, and Ren, her womanizing elder brother—helping her abilities remain a secret by altering the affected humans' memories, no one is the wiser. That is, until Karin's newly transferred classmate, Kenta Usui, finds her behavior suspicious. And to make matters even more complicated, Karin feels her blood reacting unusually to Kenta's presence.

Creatures known as Shokujinki have been secretly living alongside humans for hundreds of years. Though they may look like humans, Shokujinki are able to transform into uncontrollable beasts with gigantic claws and consume humans to survive. The equally secretive Kifuuken dojo specializes in killing Shokujinki by cutting off their arms, and is the only force preventing unchecked Shokujinki domination. Toshihiko Momota, the son of the leader of the Kifuuken, is instantly charmed by a mysterious woman named Yuka Kamitsuki. Their relationship is complicated, however, because unbeknownst to them both, Yuka is a Shokujinki and Toshihiko is sworn to kill her. Meanwhile, the Kifuuken is having a crisis of confidence as Toshihiko's brother Kazuma pushes against tradition and tries to modernize the Kifuuken. As emotions are strained and the secrets of both the past and present are revealed, who will live, and who will be eaten?

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.