Rei, the protagonist, is a high school graduate preparing for university. Without warning, his soul is summoned to the world of his novel, "Trinitas Mundus," a world created by three gods of heaven, earth, and humanity. He is transferred into the body of a holy knight, Rei Arklight, from a thousand years in the future. Why was he chosen? What is his purpose? With no explanation, he is thrust into his own fictional world and must survive. He possesses knowledge of this world's laws but has some sealed memories. He survives with a female mercenary he helped by chance. He becomes entangled in the fate of this world, despite his intentions. This is a story of a timid young man, Rei, growing with the help of those around him. He has an excellent physique and world knowledge, making him somewhat of a cheat character. His magic is particularly powerful, but his mental weakness prevents him from becoming an overpowered protagonist. This shares a similar worldview with "Dream Life," though the timeline differs slightly. The novel has been adapted into a book series.