Having reassembled, the Ninja head into the underground swamp where the Vermillion have been bred in order to rescue the captured laborers, Wu and Cyrus Borg, while Kai is determined to track down and confront his father.
Zane, still struggling with P.I.X.A.L.'s absence, searches for Borg while Lloyd goes after Wu, while Cole and Jay find the prisoners, including Elemental Master of Metal Karlof and the Royal Blacksmiths.
Lloyd soon finds Wu under guard by Raggmunk and Blunck, who are bemoaning Machia's recent promotion over them, and attempts to rescue him but fails.
Cole and Jay attempt to rescue the various craftspeople, while the third Time Blade returns to Ninjago and is retrieved by Aria and the Time Twins.
Meanwhile, Kai confronts his father believing him to be a traitor, only to be stopped by his mother and Nya, and then to learn that Krux, after returning to Ninjago alone, blackmailed them into aiding his plans for conquest.
They explain that these plans include a monstrous weapon known as the Iron Doom, which combines Ray's blacksmithing with Cyrus Borg's technology and the Time Blades to travel through time, which the Time Twins intend to use to conquer all of time.
Unfortunately, before they can act to stop it, the Time Twins, Aria, and their forces arrive and inform Kai and Nya that they will help them to retrieve the final Time Blade from its hiding place.
"Aria switched sides again" Kai mumbled to Nya
"Or is she pretending" Nya mummbled back