In the molecular biology department of a major university, Komada and Koshigaya do more than just teach. They are also investigating demon viruses, which cause people to morph into grotesque creatures with a craving for human flesh. While conducting their research, the pair encounter Sayaka Murakami, the granddaughter of a famous fortune teller. Feeling compelled to help her find her missing grandfather, Komada and Koshigaya learn that a group of thugs is pursuing Sayaka. To make matters more sinister, these perpetrators seem to have a connection to the demon viruses.

Christopher Chris Chiaki is an easygoing guy who keeps failing his college entrance exams well into his mid-twenties. His days are occupied with Kendo practice, visits to his family's shrine, and dreaming of his high school reunion. When his spirit is suddenly transported to the world of Byston Well, Chris becomes Garzey's Wing, a legendary holy warrior. The Metomeus tribe summoned him to help liberate them from slavery, but unfortunately, Chris has no knowledge on how to be a holy warrior, and moreover, only has an incredibly dull sword which he salvaged from a corpse. To make matters more complicated, there is another Chris who is still in the normal world! He cannot control the events in Byston Well, but is tied to the fate of the other Chris. The young man must struggle and adventure in a world of magical creatures and mysterious foreigners.

Chizuru, a cheerful girl with a history of unsuccessful romance, is planning to break up with her boyfriend, Yuudai, since he never seems to reciprocate her feelings. However, as she arrives at what she plans to be their final date, Yuudai presents her with a gift that turns out to be an energetic and troublesome mini donkey. While Yuudai was hoping that today would be the day he could finally summon enough confidence to let Chizuru know the depth of his feelings, a series of misunderstandings threaten to tear the couple apart forever. With a rambunctious mini donkey doing its best to mend their relationship, Chizuru and Yuudai each wonder if they are capable of loving and being loved in return.

Kimihiro Watanuki can see spirits and other assorted supernatural creatures, which is quite a bothersome ability he strongly dislikes. On the way home one day, while plagued by some spirits, he is inexplicably compelled to enter a strange house. There, he encounters Yuuko, a mysterious woman who claims to be able to rid him of the ability to see and attract the troublesome creatures—for a price. She demands that he work at her store that grants wishes to people, and thus begins Watanuki's adventures through weird and wonderful events.