Lego Ninjago: Masters Of Spinjitzu: Season 0, Episode 7

0 - 7: Way of the Ninja

A solitary wanderer meets Kai, a young sword-maker, and his sister Nia in their small farming village right before a terrifying skeleton army arrives, ransacking their shop. The army takes a map hidden by their father years ago and Nia! The wanderer turns out to be Sensei Wu, an old friend of their father's. He promises to help Kai find his sister, but first Kai must become a ninja and master the art of spinjitzu.