Koyomi Araragi is studying hard in preparation for his college entrance exams when he begins to notice something very strange: his reflection no longer appears in a mirror, a characteristic of a true vampire. Worried about the state of his body, he enlists the help of the human-like doll Yotsugi Ononoki and her master Yozuru Kagenui, an immortal oddity specialist. Quickly realizing what is wrong with him, Yozuru gives him two choices: either abstain from using the vampiric abilities he received from Shinobu Oshino, or lose his humanity forever. [Written by MAL Rewrite]

Now that Koyomi Araragi and Hitagi Senjougahara have graduated, very few familiar faces remain at Naoetsu Private High School, one of them being Kanbaru Suruga, holder of the Monkey's Paw. When she begins to hear talk of a mysterious being known as the "Devil," who will magically solve any problem, she immediately thinks these rumors are about her and decides to investigate. She discovers the Devil is actually Rouka Numachi, a former rival from junior high who is providing free advice to those who seek her out now that she is no longer able to play basketball due to a leg injury. Acting as a collector of misfortune, she enjoys relieving the stress of her clients by providing them with the false hope of having their problems solved. Although Kanbaru sees no real harm being done, she reprimands Rouka for lying and heads home, relieved she is not the cause of the rumors. But when she finds that her left hand has reverted back to its human form, she may have a reason to worry after all... [Written by MAL Rewrite]

It is the dark century and the people are suffering under the rule of the devil, Vandel, who is able to manipulate monsters. The Vandel Busters are a group of people who hunt these devils, and among them, the Zenon Squad is known to be the strongest busters on the continent. A young boy, Beet, dreams of joining the Zenon Squad. However, one day, as a result of Beet's fault, the Zenon squad was defeated by the devil, Beltose. The five dying busters sacrificed their life power into their five weapons, Saiga. After giving their weapons to Beet, they passed away. Years have passed since then and the young Vandel Buster, Beet, begins his adventure to carry out the Zenon Squad's will to put an end to the dark century.

Two OVA episodes are bundled as DVDs with each of volumes 6 and 7 of the manga. The first OVA is a prequel story written by the manga's author. Before the beginning of the main story, Rea and Chihiro have already met at a certain place: an outdoor hot-spring bath. The second OVA takes place after the series (effectively episode 14). The Furuya family finds a mysterious young girl hiding under the household temple.