In the real world of 2030, a disaster known as the “Crimson Fog Tide” sweeps across the globe. In its wake, 1% of the population is chosen to enter a mysterious domain called the “Cthulhu Deduction Space.” The “real world,” where everyone else remains, is afflicted by “cognitive contamination,” and the only cure comes from the “Clarity Potion” inside the Deduction Space. The story follows Lin Shen, a counselor who is drawn into three scenarios within the Deduction Space. Through strategy and solving one crisis after another, he ultimately uncovers the truth behind the disaster and succeeds in saving humanity. Combining Cthulhu elements, infinite loops, mystery and deduction, System missions, and an apocalyptic wasteland, this is a battle of wits and courage.