"Sasuke Sarutobi" is an average college student at Kyoto University studying time slips as a hobby until the day he falls into a time slip himself, transporting him to the Sengoku Period. Upon arrival, Sasuke encounters several warlords he could only ever dream of meeting: Toyotomi Hideyoshi, Tokugawa Ieyasu, and the famous "Demon King of the Sixth Heaven" Oda Nobunaga, who takes him in as a vassal. Introducing several modern concepts to the warlords varying from playing tennis to sending chain letters, Sasuke finds his place in an old but utterly new world.