Two thousand years ago, countless meteorites landed on the earth. Along with the mutation of animals and plants, the energy was revived. People called them alien beasts or card beasts. Humanity gradually fell into gradual extinction. Later people can become stronger through practice. At the same time, cards also appeared, and people discovered that they could use cards to help resist alien beasts. They could use the cards to establish a summoning contract with the creatures in the cards, and humans would help the creatures in the cards to increase their strength. The creatures in the cards help humans resist, but there are uncontrollable factors. There are also some who hate forming contracts with people or will kill the summoner. If the summons is successful and they can fight side by side, they are called card callers. Those without the assistance of card creatures are called hunters.
