Where is airing: Cartoon Network
How many episodes in 12 season: 16 episodes
The Mechanic and his henchmen infiltrate an old electronics warehouse in search of a mysterious motherboard. The ninja learn of the heist and arrive to thwart the attack. But they're completely in the dark as to what the Mechanic wants with it, so they head to the Mechanic's headquarters looking for clues. There, the ninja find the legendary, unreleased arcade game called Prime Empire.
When the ninja discover that Jay has disappeared into the arcade game, they interrogate the Mechanic, hoping to learn who the mysterious Unagami is and how they can get Jay back. But the Mechanic refuses to speak.
More and more people are disappearing in Ninjago City, while the ninja scramble to unlock the secrets of the Prime Empire arcade game. They decide to take the game to Cyrus Borg, hoping he can help them decode the programming and release all the players who have been taken (including Jay). Meanwhile, the Mechanic and his henchmen are resting in Kryptarium Prison when the jail's security systems begin acting up.
The ninja materialize inside Prime Empire and go immediately on the run when they discover a squadron of Red Visors waiting for them!
Okino is a serious, duty-bound Samurai warrior who is unaware that Prime Empire is a game, since he is part of it. His job is to lead players through the three dangers of Terra Karana - the Forest of Discontent, the Cliffs of Hysteria and the Maze of the Red Dragon where the first Key-tana is located.
The Samurai guide, Okino, leads the ninja into the first of Terra Karana's deadly challenges: The Forest of Discontent, made up of deep, dark woods, filled with booby-traps.
The ninja arrive at the Cliffs of Hysteria where they meet Shifty, a merchant who runs a table at the base of the cliffs. Shifty sells the ninja some grappling hooks and rope. Unfortunately, the ninja don't have enough money to buy the "Rope of Supreme Durability" and opt instead for the "Rope of Questionable Integrity".
As the ninja and Okino approach the Maze of the Red Dragon, Unagami uses his control over Prime Empire to briefly "pause" all the players except Okino. He appears before Okino, urging Okino to betray the ninja and not help them against the fearsome Red Dragon that awaits the ninja at the heart of the maze. If Okino betrays them, Unagami promises to bring him with into the real world.
Having obtained the first Key-tana, the ninja enter the second of Prime Empire's game zones, Terra Technica, where they learn that the second Key-tana can only be won by winning a dangerous race called the Speedway Five-Billion.
The ninja appeal to Scott for help in obtaining 5 race cars. Scott shows them his junkyard where he has 5 vehicles that may be repairable in time. Lloyd heads off to the racetrack and watches a live race, hoping to learn as much as he can about the brutal Speedway Five-Billion.
Red Visors discover the location of Scott's garage and Scott sacrifices himself to buy the ninja a chance to escape and they race off. The ninja enter the Speedway Five-Billion in the nick of time, just as the race is starting, and find themselves quickly overwhelmed.
Devastated by the loss of Cole and Kai, the surviving ninja push on into Prime Empire's third and final game zone - Terra Domina.
Zane and P.I.X.A.L. visit an old childhood contact of Milton Dyer's who tells them that Dyer used to frequent an old video arcade hall called Buddy's Pizza. They head there to search for Dyer.
The Mechanic's henchmen capture Master Wu and bring him to the Mechanic's warehouse. The Mechanic uses him as leverage to coerce Zane into revealing the location of the motherboard.
Jay must stand alone against Unagami in the end-game, after Nya loses all her lives, yet Unagami has a bigger battle in facing the truth about his own identity.
When Unagami breaks into the real world and terrorizes Ninjago, Jay, Zane and Pixal attempt to prevent disaster by reuniting him with his creator.
