S01E01 Catnap Burglar
Bakufu, the famous Ninja master, literally drops out of sky (hence the hole in the school's roof) and offers to teach at Shuriken School. The Principal doesn't dare refuse, but Bakufu's fee is exorbitant.
Zumichito tells our three heroes the story of one of his epic adventures. At the time he was a young ninja and a Katana student stole the Jade Dragon from him, a priceless treasure that he was guarding. Just as he'd managed to get the treasure back off the thief - who had taken refuge on a boat on Lake Akayama - a huge monster of a fish attacked them. Zumi had no choice but to abandon the Dragon so as to save his adversary from drowning. Since that day, the treasure has lain at the bottom of the lake.
Eizan Kaburagi and his friends experience their first year at a ninja school, where they learn only the finest forms of education there are… such as how to pass through walls, disappear into clouds of smoke and fly over rooftops.