The Hatching (flashback)
After Wu and Garmadon stripped Krux and Acronix of their abilities to control Time via the Chronosteel-forged Time Blades after a battle at the Monastery of Spinjitzu, the two used the blades to create the Temporal Vortex in order to dispose of the blades throughout the ages to prevent them from ever falling into the wrong hands. After they entered the vortex, Krux and Acronix broke free of their captors and soon followed the blades, ultimately becoming lost in time as a result. As they disappeared, a vision of the future indicating the day another vortex would open appeared inside the vortex, which Wu saw.
Pause and Effect (flashback)
While Acronix would remain in the vortex with the Pause, Forward, and Slow-Mo Time Blades for the next forty years, Krux would somehow escape the vortex and land in the woods below the monastery and escaped the scene, but missed the arrival of the Reversal Time Blade, which landed directly after him.
Using the vision he saw in the vortex, Wu waited at the remains of the monastery for Acronix's arrival. As predicted, the vortex opened and Acronix emerged from it. Wu then immediately challenged him, saying he's been waiting decades for this.
After a short fight, Acronix almost falls to his death, but is saved by Wu, asking him to yield. After he does, he begins to pull him up, saying that the forty year-long battle between the Hands of Time and the Elemental Masters finally ended at exactly six o'clock. As his watch stuck six o'clock, the vortex opened again, this time releasing the Forward Time Blade. As it landed, it caused all of time to move forward a full minute. After obtaining the blade, Acronix managed to overpower Wu and strike him with it, ultimately causing him to begin to rapidly age.
After escaping the area after the ninja arrived and fought him, Acronix reunited with his brother Krux, who was going under the alias of Dr. Sander Saunders, after forty years of being stuck in the vortex.
While the Vermillion operations collecting scrap for their master plan was being carried out, the vortex opened over the Eastern Sea of Sand and released the Slow-Mo Time Blade, slowing down time briefly as it landed. After feeling its effects, the Hands of Time ordered Machia to order the Vermillion warriors to go after the blade. While the Vermillion managed to recover the blade first, the ninja ultimately escaped with the blade after seizing it from them.
As the ninja began to carry out their plans of infiltrating the Vermillion Swamps, Acronix managed to use his BorgWatch to locate where the vortex would open again to release the Pause Time Blade. After traveling to the landing site at the Glacier Barrens, the vortex opened as Acronix predicted, releasing the Pause Time Blade, causing time to pause for a moment after it landed. After its effects wore off, Krux immediately claimed the blade.
After Kai and Nya reunite with their parents Ray and Maya, they explain how Wu saw the vision in the vortex and how the Hands of Time planned on creating the Iron Doom, a time-traveling mech that could travel back in time through the Temporal Rift with the use of all four Time Blades.
After the Hands of Time obtain the Reversal Time Blade after Kai and Nya recovered it from the Boiling Sea, they brought all four Time Blades to the Vermillion Swamps, where the Iron Doom was ready for use. After pausing Zane, Samurai X, and Cyrus Borg with the Pause Time Blade as they attempted to disable the Iron Doom, Acronix and Krux inserted the four blades into the time apparatus created by Borg, ultimately powering on the Iron Doom. After all of the Vermillion, Krux, and Acronix boarded the mech, the Iron Doom created the vortex directly above it. The Iron Doom then launched itself into the vortex as the Fusion Dragon carrying Wu, Nya and Kai entered directly behind it just before the vortex closed.
The Iron Doom ultimately used the vortex to travel back in time to the moment after the past selves of Krux and Acronix were lost in time, landing in front of the Monastery of Spinjitzu, where the future selves of Krux and Acronix ordered their Vermillion warriors to attack the past Elemental Alliance.
Despite their upper hand in the fight, they soon began to lose it after Kai and Nya, posing as their parents, explained how to defeat the Vermillion. Even after the Vermillion merged with the Iron Doom, the Fusion Dragon and its owners Kai and Nya were still too strong to beat. Acronix then suggested traveling to the future, where they were sure to have a victory, using his helmet to cause the Iron Doom to open the vortex. After dodging the Fusion Dragon, the Iron Doom entered the vortex. However, Kai, Nya, and the fully recovered Wu managed to use the past Reversal Time Blade to reverse time in order for them to enter the vortex as well. Just before entering the vortex after the Iron Doom, Wu tossed the past Reversal Time Blade to his past self.
As the Iron Doom traveled to the future, Acronix explained to Krux that by going far enough into the future, there would be no one that could stop them. At that moment, however, they were confronted by Kai, Nya, and Wu. After expressing their anger, they engaged the trio in a final battle. As the Iron Doom began to pass by the present, Wu made the ultimate sacrifice and ripped the Reversal Time Blade out of the time apparatus, causing the Iron Doom to spin out of control. Just before he forced Kai and Nya to the present, Wu gave them the Reversal Time Blade, saying he was "putting off until tomorrow for what cannot be done today". As Wu confronted a defeated Krux and Acronix, he then tells them that it indeed ends now. As the three fought, the Iron Doom became lost in time and was trapped in the vortex as a result.
Back in the present, the vortex releases Kai and Nya near the others in the Vermillion Swamps, where they use the Reversal Time Blade to cure their aging father of the time punch inflicted by Acronix earlier. After realizing Wu was now gone, the ninja tasked Lloyd with being in charge. As his first order, he explained that they must dispose of the Time Blade, as well as saying that they will not rest until they find Wu.
After throwing the Reversal Time Blade to Kai and Nya and off the Iron Doom, Wu stayed behind and prepared to fight the Time Twins. However, he was struck with electricity from the inside of the Iron Doom. Striking his staff, the Time Twins and Wu were transported to the Fire Temple, where they saw past versions of Kai and Lloyd. Krux attempted to change the past, but Wu stopped him and unintentionally transported himself and the twins back to the Iron Doom, becoming younger in the process.
Krux and Acronix deduced that Wu was affected by the energy of the Time Blade, which was allowing the Iron Doom to continue moving through the temporal vortex. As the Iron Doom drained a lot of his energy, he de-aged into a teenager. The Twins realized they would have control of time and attacked him again before they were transported to the Temple of Light. Wu again stopped the Time Twins from interacting with the past ninja and the three were warped back to the Iron Doom once again.
As they fight continued, Wu and the Time Twins would warp across several time periods, until they ended up back on the Iron Doom, where Wu de-aged into a child. Krux mocks Wu's new form and his bowl-cut hair, stating he would be no threat but Wu was not done and threw his staff at Krux and ran toward the time apparatus. When Acronix protested against this, Wu responded that the Hands of Time were no more than "second-hand thugs" before using the Reversal Blade energy to halt the Iron Doom entirely.
With the Iron Doom broken and completely still, an infant Wu floated through the temporal vortex before he somehow managed to escape.
- 65. "The Hands of Time"
- 66. "The Hatching" (flashback)
- 69. "A Line in the Sand"
- 72. "Pause and Effect"
- 73. "Out of the Fire and Into the Boiling Sea"
- 74. "Lost in Time"
- 77. "The Oni and the Dragon" (indirectly mentioned)
- 92. "Saving Faith" (flashback)
- 5. "Golden Hour"
- The Book of Spinjitzu (pictured)
- Anything inside the temporal vortex will not age, as demonstrated by Acronix being stuck in the vortex for forty years and, after coming out, looking exactly like he did when he first entered the vortex.
- However, this may be because Acronix has been inside for only minutes, but outside the time vortex, 40 years have passed.
- Both times the Iron Doom travels through the temporal vortex, glimpses of numerous characters and events from the past can be seen. These include Nadakhan and Kai on the beach from "Misfortune Rising"; Flintlocke; P.I.X.A.L.; Cloud Kingdom; Nadakhan; Destiny Cole; unmasked Deepstone Nya; Golden Techno Zane; one of the ninja being frozen by Nadakhan in "The Way Back"; Deepstone Nya; Monastery of Spinjitzu; Cole, Lloyd, and Nya on Tiger Widow Island; Morro in possession of Lloyd's body; old Lloyd; and Nadakhan's duplicates from "The Way Back".
- Events from past and potential future seasons can be seen scattered around the vortex when either traveling forwards or backward in time. Wu saw the foreshadowed time of Acronix's return which was 40 years later.
- As demonstrated multiple times, it is possible to become stuck inside the vortex through several different means, a process which is described as being "lost in time."