The Makai fight a secret war against the demon forces known as Horrors, evil creatures that manifest themselves through darkness to devour Humanity. On the frontlines are the Makai Knights, given the task of watching over a district and eliminating any Horrors that manifest there. GARO follows the tales of the Knights bearing the title of ‘Golden Knight Garo’, and their duty to vanquish the Horrors and protect Humanity from the darkness.

Set within a hospital, located on the outskirts of town, mysterious phenomenons occur in sequence around a nurse. The nurse is suspected as the cause for some horrible cases and finds herself in danger.