While fighting foes across Ninjago City and beyond, the ninja embark on new quests and gain newfound allies as the power of their friendship is tested.
Kai promises to watch over Lloyd when Lloyd fears the loss of his father will make the path ahead uncertain- but when Wu sends them out on an errand for his new Tea Farm, Lloyd goes on a solo mission... only to discover it's a trap from a GHOST who's escaped the Cursed Realm.
When Moro gives chase to the Bounty and steals Wu's staff, Wu shares the story of Moro: the boy who wanted to be the Green Ninja - and the Ninja discover Wu's staff contained 3 symbols that lead to the Tomb of the First Spinjitzu Master which holds a mysterious relic that could alter the course of Ninjago.
The Ninja travel to the Village of Stiix to find the thief who stole the scroll of Airjitzu, but the self-serving Ronan isn't keen to sell it cheaply so the Ninja must figure out a way to make money on the docks - and when they fail to make enough cash, the Ninja decide to steal it - but have a run in with Moro and Sowlarcha.
The Ninja hear of another way to learn Airjitzu - from the ghost of Sensei Yang at his haunted temple - but there's a warning; if you are trapped in it by sunrise, you will become a ghost, too. Meanwhile, doubting she's a Water Ninja, Nya quits her training to take Ronan to her Samurai X cave...but has a run in with Moro.
Now that the Ninja know Airjitzu, they get briefed about how the next stage to finding the tomb is to get 'The Sword of Sanctuary' from Cloud Kingdom, which can only be reached from the top of the Wailing Alps. The Ninja go on the treacherous mission up the tallest peak in blizzard conditions using their mechs, but Cole struggles with his ghostly form.
In Cloud Kingdom, a realm where destinies are written, the Ninja must get the Sword of Sanctuary, a powerful relic that can see past the traps surrounding the tomb of the First Spinjitzu Master - but tensions are high as Moro's escape from the Cursed Realm has put the future in chaos, and they won't give the Sword to the Ninja unless the Master Writer meets them personally.
The Ninja now have all the items they need to get to the tomb of the First Spinjitzu Master but before they can figure out the last riddle that leads to the location of the tomb, Ronan steals the sword to give to Moro in exchange for his soul, and the Ninja and Nya are unable to stop him.
The Ninja use Ronan's airship to travel to the tomb of the First Spinjitzu Master in an underwater cave under the ocean, only to find out Moro is already there - and the Ninja must traverse the temple traps without the aid of the Sword of Sanctuary in a desperate attempt to get to the tomb first.
When Moro uses the Realm Crystal to open a portal to the Cursed Realm, ghosts take over the town - but the Ninja, in disguise, manage to get Lloyd to the center of the town and Lloyd steals the crystal...only to discover it's too late as the Preeminent arrives.
As the ghosts converge around and mobilize the Preeminent into a hulking giant behemoth, the Ninja use Airjitzu to fight the mobile beast in an attempt to slow it down - while, at the same time, Lloyd faces off with Moro, battling over the Realm Crystal; a fight that takes them in and out of different realms.
