Nigel Uno, commonly referred to as Numbuh One by his fellow KND operatives, is at a crossroads. Fighting against his very grandfather alongside his father, who was secretly the legendary Numbub Zero, had been the best thing that could happen in his life. But even life had ways to make it so that he wouldn't be able to enjoy it as he would want to. Because thanks to Grandfather, it was the world against the two of them. But help came from the most unexpected allies, and with it, Nigel's chance to defeat his grandfather without any sort of sacrifice... or so he thinks...