On the Day of the Departed, the Ninja hurriedly travel across the Sea of Sand, en-route to the Ninjago Museum of History. Upon their arrival, Wu reminds them of the holiday's significance: for remembering fallen ancestors and cherishing family. Dr. Saunders arrives, greeting Wu and the Ninja before presenting the museum's new exhibit, the Hall of Villainy, which houses life-sized mannequins of the major villains fought by the Ninja over the years, as well as a plaque describing the rare Yin-Yang Lunar Eclipse.
-
Aria looks out at the yin-yang eclipse "where did those idiots go off to on a day like this, don't they know the dangers of the eclipse"
"I'm afraid they don't" Misako sighs taking a seat next to her "will you be able to handle it on your own?"
"Is it my job" Aria replies "Speaking of that i have to get going, if something happens let me know"
"of course" Misako nods "you know... you can join me and Lloyd if you'd like"
Aria smiles slightly "thanks Misako, but I have my own family to remember"
-
The Ninja divide for their own personal memorials: Lloyd and Misako commemorate Garmadon at the Corridor of Elders; Kai and Nya remember their mother and father at their blacksmith shop; Zane remembers his father in Birchwood Forest; Jay spends time with his mom and dad at their junkyard, and Wu goes to the old monastery to remember his father.
Aria sits on the dark island as she lights a lantern, there Aria remembers her parents and sister.
"I knew you'd be here"
Aria turns to see her brother "Zero"
He sits next to her and lights his own lantern, together they released them into the sky and watched them float away.
"...do you always have to come here?" Aria asks
"Yeah" Zero replies still watching the lanterns fly away "it's the only time I get to see my little sister"
"I'm just busy" Aria looked down at her hands
"I know" Zero replies
Together they sit there in a comfortable silence.
-
Cole arrives at the Temple of Airjitzu, which is still floating in the sky. Cole confronts Yang, who he attempts to strike with the Yin Blade but misses, instead of smashing it into an orb. Consequently, the Departed Realm is opened, and the spirits of the Ninjas' old enemies escape while Cole is detained by Yang's Students.
The spirits possess five of the six mannequins in the Hall of Villainy, bringing them to life. One taking his own human form. Speaking through a painting, Yang tells the villains they can remain in Ninjago by slaying the Ninja that defeated them. Pythor then enters the museum and joins the villains as they discuss who to go after.
Chen chooses to go after Kai and Nya, Pythor chooses Lloyd, Cryptor chooses Zane, Morro chooses Wu, Kozu chooses Dareth, and the Overlord chooses Aria, which leaves Samukai with facing Jay. Pythor proposes they gather reinforcements from the Hall of Sidekicks to better have the chance of defeating their enemies.
-
Cole is imprisoned in Yang's temple, where he learns of Yang's history. Yang taught his students to master Airjitzu, and around this time he found the Yin Blade, which contains enough dark magic to imbue immortality. Yang tested the blade on himself, but its powers backfired, turning him and his students into ghosts and defacing his temple. Yang then reveals to Cole that he plans to use the Yin Blade to tear open the Rift of Return to revive himself, while the revived villains distract the Ninja so they won't thwart his plans as Cole realizes his friends are in danger because of him.
At that moment, the villains begin their attack on the Ninja all around Ninjago. With help from Eyezor and Zugu, Chen uses his dinosaur mech to attack Kai and Nya, who flee on the Raider Bikes. Cryptor and three Nindroids confront Zane in the snowy forest. Meanwhile, Samukai fights Jay as Krazi and Frakjaw apprehend his parents, and Pythor fights Lloyd and holds the latter's mother captive. Kozu and several Stone Swordsmen confront Dareth, who was responsible for taking control of the Stone Army.
Wu gets a bad feeling as Morro confronts him, though Wu is pained at having to fight his former student again, he states that he won't hesitate to do it again. However, Morro reveals he really has no intention of revenge; instead he tells Wu of Yang's plan and they set off to reunite the Ninja.
-
The Overlord arrives on the dark island to see his two kids sitting together. He sighs and just smiles. He walks over to them.
Aria felt a hand on her shoulder "Can I join you kids?"
Aria and Zero turned around fast to see their father.
"hey kids" the Overlord smiled
"papa.." Aria stared at him
"Dad" Zero said surprised
Aria stood up and got in a fighting position
"woah woah woah no need for that my dear" the Overlord put his hands up "I'm not here to fight.. I just simply came to spend this night with my kids"
"really?" Aria relaxed a bit
The Overlord smiled and sat on the beach next to Zero, he patted the empty spot next to him. Aria smiled a bit and sat next to her father. She laid her head on his shoulder and he patted her head.
"I'm so proud of you two"
-
Back at the Temple of Airjitzu, Cole breaks free and makes his way up through the temple after escaping his captors, fighting Yang's students along the way as Yang opens the Rift of Return. One by one, the Ninja defeat all the revived villains, except Pythor, who flees after realizing he can't win his fight. In the meantime, Yang does Airjitzu to reach the Rift, but Cole stops him, and a fight breaks out between them.
The Ninja reunite at the museum, telling each other what happened before Wu arrives with Morro, who the Ninja prepare to attack but Wu stops them and Morro proves his innocence by unveiling Yang's plan and how the Ninja forgot Cole. The Ninja journey to Yang's temple while Morro's spirit peacefully returns to the Departed Realm. Cole battles Yang as the Ninja fly over on the Bounty. Yang soon overpowers Cole and mocks him as being another forgotten ghost.
However, with his friends approaching and calling out to him, Cole's heightened vigor makes his arms rock-solid, and with them, he shatters the Yin Blade. This act frees Yang's students from his control, while Cole tells them to cross through the Rift, and after they do they become human again. Yang admits he failed his students and wanted to live forever so no one would forget him, to which Cole says he'll be remembered as the creator of Airjitzu.
-
The Overlord looks down at his disappearing hand "It looks like my time is almost up"
Zero stood up "then I guess it's time for me to get going"
"Don't you want to spend some more time with dad?" Aria questions
Zero smiles "I think you and dad should spend some time together, I'll see you next year"
With that Zero got on his boat and headed away from the Dark Island.
"Aria" the Overlord called out and she turned to look at him "..you... you know you're my favorite right, even as mean as it might sound, you are my favorite child. That's why i could only ask you to carry this burden of my powers, because you are my favorite and most trusted... Aria my daughter... you are my soul... my everything... tonight I can leave in peace once again cause I know you are making the right choices for yourself, my cursed child"
-
Cole persuades Yang to accompany him through the rift. Together, they ascend towards the Rift, but Yang tells Cole that someone has to remain in the temple as a ghost to be the "master of the house" due to the curse. Yang then decides to settle his own "debts" and launches the confused Cole through the Rift, just as it starts to close.
The shockwave of the Rift closing causes Destiny Bounty to have a hard landing at the Airjitzu temple. The Ninja get off the ship.
"Is everyone all right?" Misako asks
"Nothing that tightening a few screws can't fix" Zane answers
Lloyd stands up "I'm okay, but where's Cole?"
Jay looks worried "Oh, no"
"Did he make it?" Nya questions
"He was too late... He's gone forever.. I'd give anything to have him back" Jay whines
"Anything?"
"Anything" Jay repeats
Cole jumps out from behind a boulder, a human again "Even the Sonic Raider Jet?"
"Cole!" The ninja embrace him.
"You're back!" Jay shouts happily
Lloyd smiles "You're not a ghost anymore"
"hey guys look" Kai points to the temple
Wu sighs "The Temple of the Airjitzu Master has been returned to its original condition"
"It's beautiful" Zane admires it
"That would be a pretty cool place for a Ninja to train..." Cole looks up at the eclipse "you know speaking of ninja.. their's one missing right now who shouldn't be alone"
-
Aria stands on the beach alone looking up at the yin-yang eclipse. She feels an arm wrap around her and she turned to see Lloyd and the rest of the ninja next to him.
"guys.." Aria looked at them surprised "how did you know I was here?"
"you go every year" Misako replies "of course we'd know"
"we've all lost people close to us" Kai says
Cole nods "and just because your father was evil-"
"-doesn't mean that he and your mother don't deserve to be remembered" Jay finished
"We're here for you Aria, you are our sister" Zane smiles
"And you're part of our family" Wu adds
Lloyd hugs her "we'll always be here for each other"
Aria starts to cry as the other ninja join in the group hug, the Overlord stood away from the group watching them as his body faded away, he smiled and turned away take care my daughter.