Day of the Great Devourer

Day of The Great Devourer is the thirteenth and final episode of the first season of LEGO Ninjago: Masters of Spinjitzu.

Plot
As the Great Devourer breaks free from its prison beneath The Lost City of Ouroboros, Sensei Wu tells the Ninja that they "must do everything in their power to stop the Great Devourer." Nya leaves in her Samurai mech, and a moment later the Great Devourer swallows Pythor and Sensei Wu in a single gulp.

The Ninja are devastated over the loss, but are forced to retreat as the giant snake spots them. They all flee to the Destiny's Bounty and take off, the Great Devourer close behind them. As they head for Crashcourse Canyon, the Devourer begins to gain on them; in response to Zane's prediction that they won't make it in time, Nya tells everyone to throw all of their belongings overboard to increase speed. However, the Great Devourer begins eating the items that were thrown, and Cole realizes that their efforts are only making their foe even bigger.

Nonetheless, the lost ballast allows the Destiny's Bounty to reach Crashcourse Canyon, weaving away from the Great Devourer. Just as the Ninja think they've lost the snake, it strikes the flying craft with its tail, and they're all forced to abandon ship. Once they retreat to safety, the Ninja watch as the Great Devourer bites their home in half, leaving the scene afterwards. Zane says that they must go warn others of the event, though Jay has already given up and proposes the idea of living in one of the Serpentine Tombs to stay safe. Kai gives the team words of encouragement, and even though Jay is barely convinced, Kai proceeds to put his own plan into motion.

Meanwhile, the Serpentine retreat to the Fangpyre Tomb as Fangtom and Skales argue over the latter's role in Pythor's insane plot. As they leave, they spot the Great Devourer close by and quickly rush inside.

The Ninja arrive at Ed & Edna's Scrap N Junk, and Jay comes to the conclusion that his parents left. Kai whips out blueprints for the Ultra Sonic Raider, and Zane confirms that he has a recording of the Sacred Flute stored in his databanks. As the Ninja discuss their plan, the Mailman appears with mail for Ed and Edna, and the Ninja tell him that he should be leaving. The Mailman doesn't understand the situation and thinks they're referring to the Take Back Ninjago Rally - apparently, everyone is gathering in Ninjago City for an anti-Serpentine rally. While the Mailman is talking, the Great Devourer creeps up behind him, prompting him to hide inside a garbage can.

Ready to fight, the Ninja use their Tornado of Creation to draw in spare parts from the Junkyard and build the Ultra Sonic Raider. Kai tells Zane to play the recording of the Sacred Flute, but the Great Devourer dodges the attack. After several failed attacks from both sides, the Ninja use a grappling hook to keep the snake still long enough to use the Sacred Flute against it. As the monster writhes in pain, Kai notices a tiny weak point on its head - while he elaborates to his friends, however, the Great Devourer strikes the Ultra Sonic Raider with its tail, destroying the sonic cannons playing the melody of the flute.

The snake retreats from the Junkyard and Zane emerges from the attacked portion of the Ultra Sonic Raider, mostly unharmed save for the exposure of the robotic parts on the left side of his face. Jay thinks the operation was a complete failure, but Kai quickly points out they now know the Great Devourer has a weak spot on its head. As Jay retorts that there's no way that they can use that knowledge, the Ninja realize that the situation has worsened further; the Great Devourer is headed towards Ninjago City, threatening to consume the metropolis and become completely unstoppable.

The Great Devourer enters the city through the subway system and scares off everyone in the rally. Ed and Edna try to escape in their car, but the engine doesn't start - luckily, Jay arrives to blast the Devourer before it can eat them. The other Ninja join the battle and attempt to deter the monster with every attack in their disposal, but their efforts only seem to make it angry.

Meanwhile, Lord Garmadon enters the local tea shop to request their Traveler's Tea; the owner comments that only fools take that blend, but redacts her statement when she sees who she's talking to. While Garmadon waits for her to come back with the tea, he sees the Ninja losing their fight against the Great Devourer on television.

Nya and Lloyd attempt to stop the Great Devourer by wedging a street light in its mouth using the Samurai X suit, only to get stuck when the suit malfunctions. Before they can be consumed, the Devourer is attacked by the Ninja's Dragons, now merged as the Ultra Dragon. After saving Nya and Lloyd, the Ultra Dragon swoops in to attack the snake, with the Ninja cheering it on. The assault seemingly forces the Great Devourer to retreat, but as the Ultra Dragon glides to its allies, the serpent's tail shoots out of the ground and knocks the Dragon out of the air.

As the Ninja assess the damage done to the Ultra Dragon, Lord Garmadon appears behind them and asks for the Golden Weapons - their combined power can destroy the Great Devourer, but only he can wield all four at once. The Ninja are hesitant - with Jay pointing out that their mission is to protect the Golden Weapons from Lord Garmadon - but Zane admits that their foe's suggestion is more feasible than any other scenario he can calculate. Deciding that they have no other choice, the Ninja hand over their weapons, with Kai telling Lord Garmadon about the Devourer's weak spot. Although clearly pleased to have the Golden Weapons at last, Lord Garmadon stays focused on the current crisis, telling the Ninja that they must immobilize the Great Devourer so he can have a clear shot at its weak spot. As the villain runs off, Jay despairs at their task, but the Ninja come up with a plan.

Kai begins by confronting the Great Devourer alone, luring it through the street to where Cole is waiting. Cole then lures it to the billboard where Jay stands, and Jay leads it through a construction site to meet up with Zane. As Jay and Zane escape using an ice slide that Zane created, the Devourer pursues them, but right before it could consume them, Kai and Cole swoop in on the Ultra Dragon to pick them up. Rushing to a nearby building, the Ninja see that their plan has worked; the Devourer has bitten its own tail, and with its oversized body tangled among the buildings of Ninjago City, it is completely stuck.

The skies darken as Lloyd spots Lord Garmadon, standing atop a skyscraper with all four Golden Weapons in hand. He condemns the Great Devourer as the one who forced him down the path of evil, and in an act of vengeance, jumps down and impales its weak spot with the Golden Weapons. Roaring in agony, the Great Devourer explodes into green slime that covers the entire city. As the citizens of Ninjago City cheer in their victory, Skalidor and Fangtom both note that it sounds like The Devourer was destroyed, to which Skales mentions that they will need a new leader.

The Ninja notice that Lord Garmadon has disappeared with the Golden Weapons, and Kai states that they'll probably be seeing him again soon. Cole then sees that Sensei Wu is alive after all amongst the slime, and the Ninja excitedly rush over to greet him and celebrate their victory. Lloyd's mood quickly turns melancholy as he remembers that he will have to fight his own father as the Green Ninja, but the others promise to train him to his full potential before that day comes.

Trivia

 * This episode features the final appearances of Pythor and the Great Devourer, while introducing the Ultra Dragon and the Ultra Sonic Raider.
 * Jay makes a reference to the movie Jurassic Park by saying the phrase: "Objects in the mirror are closer than they appear."
 * When Nya responds to Zane with "Never tell me the odds," it is a reference to The Empire Strikes Back.
 * The pose The Great Devourer is destroyed in, with its tail in its mouth, is a reference to an Ouroboros, meaning "Serpent eating its own tail."

Errors

 * When Skalidor talks at the end of the episode, he has the voice of Acidicus.
 * During several scenes featuring The Royal Blacksmiths, Lou has the exact appearance of one of his quartet.