The story centers around a timid orphan named Mizumura Shinta who goes to a missionary school in Tokyo. His seemingly normal life changes when a beautiful half-human Romanian girl named Lilith suddenly transfers into his school. Mizumura discovers that he is actually a vampire hunter and the successor of the Romuald lineage.

The official website of the Shiki television anime series confirmed on Saturday that the anime's eighth and ninth Blu-ray Disc/DVD volumes will each include an unaired episode. The eighth volume will ship with Episode 21 and the unaired episode "Dai Futatō to Han wa" (a wordplay for "Episode 20.5") on May 25, 2011, while the ninth volume will ship with Episode 22 and the unaired episode "Dai Futatō-ichi to Han wa" ("Episode 21.5") on June 22. (Source: ANN)

In ancient times, a great battle was waged between a master mage, Enno Ozuno, and an evil demon goddess, Karuma. Unfortunately, Enno didn't have the strength to defeat her alone and was forced to call upon Zenki, a powerful protector demon. After Karuma was defeated, Enno sealed Zenki away in a pillar located inside his temple. 1,200 years after this epic battle, Enno's descendant, Chiaki, spends her days showing tourists around her hometown of Shikigami-cho and doing exorcisms to pay the bills. One day, two thieves enter the town in hopes of opening a seal in the Ozuno temple and releasing the hidden treasure from within. However, what actually pops out is a dark entity that attaches itself to the henchmen, transforming them into demonic beings. After this transformation, they begin a rampage through the temple, terrorizing poor Chiaki. It is now up to this young progeny to unleash her family's powers to summon Zenki and save Shikigami-cho from these demons, as well as the evil entities sure to follow in their footsteps.

Seventeen-year-old Tenchi Masaki grew up hearing stories about how his ancestor used a sword to seal a demon inside a cave seven hundred years ago. When curiosity gets the better of him, Tenchi goes to the cave and stumbles across the sword from the legend. Thinking that the story is nothing more than a fairy tale, he removes the blade and inadvertently releases the demon, who turns out to be a space pirate named Ryouko Hakubi. Furious about being trapped for so long, she attacks Tenchi, but he is able to repel her with the sword, awakening his inner power. After seeing this, Ryouko takes an interest in her unlikely savior and decides to crash at his place. As if it were a chain reaction, more alien women—Aeka Jurai Masaki, an uptight princess from the planet Jurai; Sasami, Aeka's sweet younger sister; Mihoshi Kuramitsu, a ditzy Galactic Police Officer; and Washuu Hakubi, a wisecracking genius—gradually come in contact with Tenchi and begin living with him. Through his encounters with these five women, Tenchi begins to learn more about his ancestry, newfound power, and the looming threat lurking beyond the skies. [Written by MAL Rewrite]