Since ancient times, people have been afraid of darkness. Because in people's hearts, there is a negative thought called "Yin I", which allows the monster "Horror" to invade and possess people. Among humans, there is a group of people who hold steel swords, pass down their family traditions to protect humans from the invasion of "Horror". They are called "Lord of the Rings Knights". They are born in darkness and hide in darkness. They have been fighting endless wars with "Horror" for generations... Mitsuki Kaoru, who aspires to become a painter, is about to hold her first solo exhibition. But she also dreamed of the "Golden Knight" picture book drawn by her father in her childhood, which made her very concerned. Although Kaoru was finally able to welcome the solo exhibition with peace of mind after talking with the psychologist Ryuzaki Kuon, the gallery owner suddenly turned into an alien monster and attacked her. At this time, a mysterious young man in a white coat appeared in front of Kaoru, and transformed and defeated the monster. And his appearance after transformation happened to be exactly the same as the "Golden Knight" drawn in the picture book...