A boy in modern-day Japan aspires to be a mastermind exerting power from the shadows. During his training, he gets hit by a truck and dies, then is reborn in a fantasy world as Cid Kagenou. Here, he maintains a presence of mediocrity so as to not stand out and pursue his dream. He cures an elven girl suffering from a disease. Cid, lying to her, explains that this world is run by the Cult of Diablos and that his organization, Shadow Garden, can defeat them. The elf, now named Alpha, "joins" and begins recruiting new members. In fact, the power struggle he described really exists. Under the alias of "Shadow", he now fights it.