Ninjago: The Challenge of the Samukai/Mask of the Sensei Bind-Up

Two books in one! Before the "Rise of the Serpentine," Samukai boasts that he can defeat Sensei Wu and his young ninja Cole, Zane, Jay, and Kai, and Garmadon gladly takes him up on his bet. Then the Masters of Spinjitzu are attacked by the one foe they can't possibly hope to defeat, the one who taught them everything they know -- Sensei Wu!