Su Mo, the God King of Chaos, was once an SSS-ranked powerhouse who ventured alone into Olympus. The Liu family had worshipped him for a hundred years, hoping to use his power to dominate the world at the summoning ceremony. When countless people gathered for the grand ceremony, the golden light faded, revealing only a tiny F-ranked creature. Furious, the Liu family abandoned him, and their century-long plans became a laughingstock. Jiang Qianyue, a fallen noblewoman, took him in and signed a contract with him. In this world, the ranks of summoned beasts are fixed and cannot be upgraded. Yet Su Mo uses Dr. Han's technology to break through this limitation, rising from F rank all the way back to SSS rank. However, whenever his energy is depleted, he turns back into that adorable little F-ranked creature. A sealed God King and an underestimated master embark together on a legendary journey.