Joy of the Warring States Period: Secrets of Jiahe

A modern nightclub veteran travels through Japan's Warring States Period, He doesn't know how to use a sword, he doesn't know about tactics, and he doesn't understand the history of the Warring States Period. Only relying on a fruit plate and boxing games to survive in troubled times. Why is he associated with ninjas? How to get involved in the major events of the Warring States Period?