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.

After hearing the rumor about a mysterious virtual reality headset which allows the wearer to participate in Versus Road game from his friend Hoshiai, Kuon finds himself acquired one of said headsets and enters the game along with 99 chosen players. There, the ring mistress of the game, Shuka, presents a golden suit of armor as the game's grand prize and explains that the first level's goal is to survive by any means necessary as their numbers are getting halved. To increase the challenge, two biomechanical demon beasts, Horrors, are released upon the players where the demons will devour those who failed to escape their grasp.