In the continent of Astraea, a man falls from the sky, possessing no memories other than his name, Yuuki. An elf named Kokkoro finds him, introducing herself as his guide in the world they are about to traverse. With Kokkoro's guidance, Yuuki is able to learn how this world works, from battling monsters to handling currency.

To earn money for their journey, Yuuki and Kokkoro decide to go to a nearby guild association to accept a simple quest. In their expedition, they meet Pecorine, a somewhat gluttonous but charming girl skilled in battle. The next day, they also meet Karyl, a cat girl specializing in magic.

After some time, a bond of friendship and camaraderie forms between them, and the four decide to create a guild of their own. As they continue their adventures, they explore the world, meet new people, and will perhaps uncover the mysteries behind Yuuki's missing memories.

In the world only the aristocrats have the power to fight the monster - mana. Even though Melida Angel was born in an aristocracy and studies at an academy developing mana users, she has no mana. To find her talent for mana, Kufa Vampir was sent to be her tutor but at the same time, he was ordered to assassinate her if she has no talent for mana. He makes a cruel decision to assassinate her because he thinks that it is a wasted effort that people who have not any mana are working hard in this world... However, he asks her, "Do you want to try to entrust your life to me?" He is not as an assassin nor a tutor. He is someone betting on his pride as an assassin tutor, to show the world what Melida is capable of!

Nur jene, die aus Familien von blauem Blut stammen, verfügen über die magische Kraft, gegen Monster zu kämpfen. Kufa, der zur Familie eines Herzogs gehört, soll eines Tages ein junges Mädchen namens Melida ausbilden - und sollte sich herausstellen, dass Melida über kein magisches Talent verfügt, hat Kufa den Auftrag, ihr das Leben zu nehmen.

Depuis que, tout petite, elle s'est perdue dans un monde étrange, Sakura Mamiya a le pouvoir de voir les fantômes. Quoique habituée à ces apparitions étranges, quelle n'est pas sa surprise quand elle voit un élève de sa classe, Rinne Rokudô, se transformer en spectre pour vaincre un esprit enragé. Elle apprend alors que cet étudiant sans le sou et toujours absent remplit tous les jours la mission d'amener les âmes récalcitrantes jusqu'à la roue de la réincarnation, où les attend leur prochaine vie...