After Kai and Nya move in with Sensei Wu and the rest of the Ninja, Nya and Jay head to the blacksmith shop in Ignacia to retrieve the weapons from the shop. The Skulkin Army, led by Wyplash, attacks Nya as revenge for Samukai's death. Nya single-handedly defeated the warriors, who are embarrassed by the defeat and she assures a worried Jay that she handled it. ("Secrets of the Blacksmith")
The Ninja argue about having the best dragon. To Zane's dismay, they have a contest to ensure who the new "Dragon Master" will be. Cole wins, but the other Ninja change the stipulations, much to his dismay and frustration. ("Flight of the Dragon Ninja")
After their defeat by the Ninja, Nuckal and Kruncha decide to steal the Ninjas' Golden Weapons as revenge. While trying to escape, they accidentally activate the Weapons. Kai nearly discovers this, but assumes that the training course has malfunctioned again. Kruncha and Nuckal return the Weapons, and bicker with each other as they return to the Underworld. ("The New Masters of Spinjitzu")
Cole visits Sensei Wu while he is drinking tea, and asks him how Lord Garmadon took over the Underworld. Wu recounts the tale of the aftermath of his and Garmadon's fight. In a flashback, Garmadon was confronted by Samukai and the Skulkin Army. A vengeful Samukai challenged Garmadon, and Garmadon accepted. Using Spinjitzu, Garmadon easily defeated Samukai and took over the Skulkin Army. Wu jokingly tells Cole that they discussed the matter over tea. ("An Underworldly Takeover")
Kai and Nya are riding on Flame, when he takes a detour, flying to the Fire Temple. There, they learn that there is a secret entrance leading to the Underworld. Kai accidentally alerts the Skulkin to his presence. Kai fights them and at first, easily overpowers them, and Nya saves him and they leave with Flame. When Kruncha and Nuckal return, they blame each other for "leaving the stove on". ("Return to the Fire Temple")
Zane visits Wu and asks about his kimono. Wu recounts the tale of Garmadon's betrayal: one night, he was caught attempting to steal the Golden Weapons and when he left Garmadon, the latter attacked him, leading to a fight, where Garmadon attempted to kill Wu. The kimono protected Wu, shooting Garmadon with lightning and charring his skin and sending him to the Underworld. Wu said that the balance was restored, but Zane jokingly said that the balance had ended after seeing the Ninja goofing off. ("Battle Between Brothers")