|“Long ago, before my people settled here, there was an older city run by this super evil sorcerer who built tunnels, and mines, and dungeons deep in the mountain. He's gone now. But the dungeons are still there so my father forbade anyone from entering them.”|
|— Vania, "Into the Dark"|
A long time ago, an evil sorcerer named Hazza D'ur owned a skull that had incredible powers and used it to rule the Dungeons of Shintaro. He was later defeated, but his bones are said to be still in Shintaro Mountain while the skull remained intact.
The Lowly entered the Dungeons of Shintaro and find the Skull of Hazza D'ur. However, when Korgran touches it, Dark Magic seeps through his body, and he drops it in surprise. The group realizes the skull is evil, so they carry it using Korgran's Axe.
Cole and Vania arrive at the Dungeons of Shintaro and catch sight of the Munce, Geckles, and Minos mining Vengestone while being watched by the Awakened Warriors. At some point, the Skull Sorcerer arrives and punishes the inmates with the Skull of Hazza D'ur for stopping. Cole then decides to jump into the scene, but he is shortly captured.
While Cole is working along with the Munce and Geckles. The Ninja attempt to save Cole, but a conflict between the two tribes allows the Skull Sorcerer to stop the Ninja.
The Ninja learn about the Blades of Deliverance and plot an escape plan. The Ninja are able to liberate the Geckles and Munce, but they all take completely different paths.
Lloyd, Jay, and Nya follow the Munce to their home. They are greeted by Murtessa who flirts with Jay. This makes Nya upset, so Murtessa challenges Jay to a fight. Nya ends up winning, but she also gains the right to be queen.
Kai and Zane are brought to Gulch after the Geckles suspected the Ninja to be with the Skull Sorcerer. In order to decide the matter, the Geckles decide to put them in a "Trial by Mino". However, Kai and Zane are able to friend the beast after removing the Vengestone armor.
Kai is elected chancellor and suggests uniting with the Munce, but the Geckles think it's a joke.
Cole and Wu are falling down a pit. Vania tries to save them, but the wings break and all three of them fall. They land on a spider web where Cole is wrapped up and is about to be eaten. However, Vania and Wu help Cole, and Cole decides to cut the spider web and they continue to fall.
They reach a stream and encounter a whirlpool. Cole uses his powers to stop it, but they are sucked in and find themselves at Rock-Bottom.
Cole, Wu, and Vania hear the Lowly's story of how they got to Rock-Bottom.
Cole, Wu, Vania, and the Lowly escape Rock-Bottom after Cole found his Elemental Energy. They then encounter the Lava Monster and are able to defeat it.
The Munce and Geckles head to the truce meeting, but when they arrive, tension rises between the two tribes. When the Ninja are able to break it up, everyone flees after hearing the sound of Grief-Bringer.
Cole, Vania, Wu, and the Upply are running away from the Lava Monster when they stumble across some mine carts. They decide to ride it and end up at the Heart of the Mountain. While they are exploring, they discover Cole's mother performed the Spinjitzu Burst. Cole tries to perform it but gets frustrated after he fails multiple times.
The Geckles and Munce take refuge inside the Geckle Strong-Cave. Tension continues between the two tribes until they finally apologize to each other after they couldn't find another way out.
The Skull Sorcerer, Grief-Bringer, and the Awakened Warriors arrive and the Ninja decide to surrender themselves and allow the Geckles and Munce to remain free. The Ninja turn themselves in, but the Skull Sorcerer lies on his promise and also captures the Geckles and Munce.
While Cole is busy fighting the Lava Monster, he doesn't realize the mine carts are headed straight to the lava, so he tries to save them. The Lava Monster gets in his way, but this doesn't stop Cole from destroying the beast and saving everyone inside the mine carts.
Cole and the Upply spot the Ninja locked up in a cage while the Geckles and Munce are back to working in the mines. Fungus and Korgran are able to give a key to Murtessa while Cole and Plundar retrieve the Blades of Deliverance.
During the execution ceremony, Grief-Bringer doesn't come out due to Cole throwing a rock at an Awakened Warrior. The Skull Sorcerer checks to see what's going on and spots Cole ready to fight him. Fungus and Korgran then jump into action and the Geckles and Munce liberate themselves. Adam and Plundar help free the Ninja to join in on the fight.
The Ninja, Upply, Geckles, and Munce are fighting the Awakened Warriors and Grief-Bringer. Despite being overwhelmed, they receive aid from Vania and the Winged Guards of Shintaro. Meanwhile, Cole is fighting the Skull Sorcerer and the Skull of Hazza D'ur. The Skull Sorcerer destroys the Blades of Deliverance he uses the Skull of Hazza D'ur to blast Cole.
Cole then remembers the promise he made to his mother and unlocks the Spinjitzu Burst, destroying the Skull of Hazza D'ur. With the destruction of the skull, the Awakened Warriors and Grief-Bringer become lifeless and return to a pile of bones. Vangelis also loses his costume and begs for mercy, but Vania informs Hailmar to take him away.
- Skull Sorcerer (formerly)
- Awakened Warriors (deceased)
- Grief-Bringer (deceased)
- Hazza D'ur (deceased)
- Dire Bats
- Giant Spiders
- Lava Monster (deceased)
- 146. "Into the Dark"
- 147. "The Worst Rescue Ever"
- 148. "The Two Blades"
- 149. "Queen of the Munce"
- 150. "Trial By Mino"
- 151. "The Skull Sorcerer"
- 155. "Grief-Bringer"
- 156. "Masters Never Quit"
- 157. "The Darkest Hour"
- 158. "The Ascent"
- 159. "The Upply Strike Back!"
- 160. "The Son of Lilly"