Across the valley, a drumbeat echoes. For ten days, the drum will call the mountain ryus to war, including the samurai kids from the Cockroach Ryu. Only Japan’s feudal emperor can stop the war, so Niya and Sensei Ki-Yaga set off on a grueling journey with all the Cockroaches, whose firm friendship and unusual skills must be put to the test in order to beg the Emperor to maintain peace. Sensei Ki-Yaga is respected and wise, but unfortunately, the last time he encountered the Emperor, the Emperor threatened to cut off his head. All seems hopeless until Ki-Yaga guides the Cockroaches to meet with the Owl Ninja clan. Samurai and ninja are supposed to be enemies, but can these two groups somehow work together to save the sensei and stop the battle in time?