To find the mother for his loving daughter, the Grand Heavenly Master of the Immortal World decides to descend to earth and marry into the mother's household. As such, he becomes a live-in son-in-law who is detested by everyone. Although the Grand Heavenly Master has lost all his power, there is still no way that the prince from the Demon World, or someone who has a cheat system at hand would be a match for him...