Episode Title:Codename: Arcturus.Episode Description:After Pythor and a group of Nindroids free the Overlord from the submerged Mechdragon, Wu and Garmadon discover that Pythor and the Nindroids have a plan known as "Project: Arcturus". P.I.X.A.L. dispatches Kai to follow a group of Nindroid convoys in the X-1 Charger. After a lengthy chase, Kai is captured by Pythor and the Nindroids. The ninja regroup and head to the Lost City of Ouroborus, where they discover an underground rocket ship - Arcturus. After freeing Kai and battling several Nindroids, the ninja make a last-minute decision to board the rocket ship, as it blasts off into space.