Shiki Toono awakens in a hospital ward possessing the ability to see invisible lines. These slender threads, which constitute all matter in Shingetsutan, instantly obliterate an object when severed. Shiki finds that tracing the lines of an object leads to its imminent destruction. While concealing his supernatural vision, Shiki attempts to live his sophomore year in peace. However, this tranquility is brief; on his way home from school, Shiki encounters a mysterious woman with bright red eyes. After a sudden psychotic episode, he appears to kill the woman and collapses shortly thereafter. As if matters could not worsen, Shiki is attacked by a pair of demonic hounds the following day. Facing certain death, Shiki is rescued by the timely arrival of the same woman from the previous day. She introduces herself as Arcueid Brunestud, a vampire princess. Deciding to cooperate, Shiki and Arcueid set out on a journey to uncover the truth regarding their lineage and the recent series of murders in the town.