An unknown mist descends, plunging the world into a card game era. Mysterious fog events occur frequently around the globe, each concealing a different world where various functional Mist Cards can be obtained. Li Yi, a high school student in the Nanxing City Spring Center Mist Task Force, uses a universal card search map during a pre-college practical simulation test in the Mist World. The map displays circles of different colors. White circles grant weapon cards, such as the piercing Ice Bone Long Sword. Green circles provide ordinary supply packages, yielding Mist Energy Cards and unit cards like the Gro Hound. From then on, Li Yi thrives in the Mist World, discovering powerful cards such as the Reta building card and the hero card, Sword Saint Agulas.