Meteors fell to the planet. These meteors carried life in the form of powerful, chaotic, uncontrollable genetic material.

These are Monsuno Monsters.

Since people over the world dream Monsuno tamer; exploring the world of the Mon, discovering new species, and making good friends along the way. There is an infinite array of creatures too varied to fully comprehend. Hundreds! Perhaps Thousands, meticulously fashioned by the forces of nature in all its glory as only Nature can. And no matter what corner of the world you find yourself in, you'll find Monsuno Monsters there as well! Soaring overhead, skimming the clouds, and riding the currents undersea! Sharing the mountain's majesty and animating our many lush green forests, happily making their homes in fields and grass! Even our sprawling cities are teeming with them.

The Hunter Elite Tactics Squad (HETS) is a government organization established to maintain peace between the world. Hunting down ferocious beasts known as Behemoths now stalk the earth. Arthur Pendragon, a prodigy graduate high school student, becomes one of the members for the organization.