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. Toono Shiki was involved in a major accident in his childhood. He was so severely injured that people thought he was dead, but he miraculously survived. However, due to that incident, Shiki is sent away from the Toono household and put into the care of a distant relative's family.Ever since the accident Shiki has changed. He now sees lines at which things and living beings completely "break" when stabbed with a blade. Troubled by this ability, young Shiki is given a pair of glasses by a women he calls Teacher, which stop the "lines of death" from being seen. Thanks to this, Shiki was able to live normally up until now.But then he receives a sobering letter. The head of the Toono household — his father's household — has died. By orders of the new head of the household, he must return at once to the Toono house.Shiki, now a high school student, thus returns to the Toono household, where all does not seem to be right...