Ten years after the Fourth Shinobi World War, Naruto Uzumaki had finally achieved his goal, being elected as the Seventh Hokage of the Hidden Leaf Village. Ever since the sealing of Kaguya Otsutsuki, the end of Infinite Tsukuyomi, and the failure of the Eye of the Moon Plan, devised by Madara Uchiha as a means of taking over the world, the world has been relatively peaceful. Having finally experienced the fruits of his labor, Naruto wanted to share them with the rest of the world through reform. His first act as Seventh Hokage would be to gather all the leaders of each nation, and form the United Shinobi Nations.

After the foundation of the United Shinobi Nations, Naruto would then work toward rebuilding the Valley of the End, which he and Sasuke destroyed, and renaming it the Valley of the Beginning, in honor of their new era of peace. Once the construction of the Valley of the Beginning was finished, Naruto had the United City created, a metropolis for all nations for enjoy. Lastly, Naruto established the Underworld, an underground passage that would be used link all the nations together, and allow the trading of goods. With all Naruto had done, he had effectively begun the First Reign of Peace.

One hundred years passing, the First Reign of Peace had come and gone, as well as nine others. As a new year begins, the Eleventh Reign of Peace has initiated. Younger, and more capable, leaders have been chosen, and the world has progressed quite finely. However, over time, the Underworld had been completely dominated by crime, with the United Shinobi Nations losing sovereignty over it, and a mysterious being named Black Kaguya has been randomly causing chaos amongst all countries. With trouble on the rise, the cooperation of the world has been even more resounding than before. All for the sake of maintaining world peace.