Shiki Toono wakes up in a hospital ward with the ability to see invisible lines. These thin threads, which make up all matter in Shingetsutan, instantly destroy an object when severed. Shiki discovers that if he traces the lines of something, its destruction soon follows. While keeping his supernatural vision a secret, Shiki proceeds to live his sophomore life in peace. However, this peace is short-lived when Shiki encounters a mysterious woman with bright red eyes on his way back from school. Following a sudden psychotic lapse, he appears to kill the woman, and passes out shortly after. As if things couldn't get any worse, Shiki is assailed by a pair of demonic hounds the next day—facing certain death, Shiki is saved by the timely arrival of the same woman from yesterday. She introduces herself as Arcueid Brunestud, a vampire princess. Deciding to team up, Shiki and Arcueid embark on a journey to uncover the truth behind their lineage and the recent string of murders around town. Shiki Tohno sustained a life threatening injury as a child, and due to that incident he was sent away from the Tohno household and was given to a relative to be raised. Years later, when Shiki is in high school, the head of the Tohno household—his father—dies, and he is ordered to move back in by his sister Akiha, who is the new head of the household. However, Shiki holds a huge secret. Ever since that injury, he has been seeing lines on objects, and only with a special pair of glasses is he able to stop seeing them. Also he is unable to remember anything well from the time before his accident. The day he moves back to the Tohno household is the day he stumbles upon a woman named Arcueid Brunstud and decapitates her with one stab of his knife in a temporary fit of insanity. When she suddenly showed up beside him later alive and well, and ask him to be her bodyguard, Shiki's journey to unravel the mysteries of his past begins.