Lego ninjago reader #1: way of the ninja

Masters of Spinjitzu: a new force to save the world! The legend of Spinjitzu begins. . . . The son of a blacksmith, Kai?s only dream is to master his father?s craft. Until the day an army of skeleton warriors raids his villages and kidnaps his sister, Nya. Kai?s only hope of rescuing his sister lies with Sensei Wu, a mysterious old man with a mission. Sensei Wu promises to teach Kai Spinjitzu. Will it be enough to save Nya?