Since Lord Garmadon's disappearance from the Underworld, NINJAGO Island has been at peace. The young ninja have grown complacent and lazy, their skills rusty from lack of use.

Unbeknownst to them, Garmadon lurks in the shadows, waiting for the right moment to strike. His young son, Lloyd, lives among the ninja, unbeknownst of his father's dark legacy.

One day, Lloyd stumbles upon an ancient scroll depicting the Serpentine tribes. Intrigued and reckless, he unknowingly unleashes these ancient foes upon NINJAGO Island.

The Serpentine are a race of snake-like beings, each tribe unique in its abilities and appearance. Their leader, Pythor, is particularly menacing with his power of invisibility.

Pythor wastes no time in hatching a devious plan. He intends to bring back the legendary Great Devourer, an all-consuming snake of immense power.

The ninja are initially overwhelmed by the sudden attack. Their rusty skills are no match for the cunning and power of the Serpentine.

Lloyd feels guilty for unleashing the Serpentine. He decides to train harder, determined to make things right and protect NINJAGO Island.

The ninja, inspired by Lloyd's determination, begin rigorous training. They slowly regain their strength, mastering their elemental powers once more.

Despite their efforts, Pythor successfully awakens the Great Devourer. The monstrous snake wreaks havoc, threatening to consume everything in its path.

The ninja are shocked by the size and power of the Great Devourer. They realize they must unite their powers to stand a chance against this beast.

Meanwhile, Garmadon watches from the shadows. He understands that the Great Devourer is a threat to his own plans, but he remains undecided on his course of action.

The ninja confront the Great Devourer in a fierce battle, but their combined powers are not enough. The beast seems invincible, its scales impenetrable.

In a surprising turn of events, Garmadon joins the fight against the Great Devourer. He knows the beast's weakness - it can only be defeated by someone wielding all four golden weapons of Spinjitzu.

Garmadon takes up the weapons and launches a powerful attack on the Great Devourer. His assault wounds the beast, but it still remains a formidable adversary.

Seeing their father's bravery, Lloyd is inspired. He realizes that he too must play his part in this battle. He joins Garmadon, ready to face the Great Devourer.

Lloyd's powers have grown significantly. With a burst of energy, he manages to distract the Great Devourer, giving Garmadon an opening to strike.

Garmadon seizes the opportunity and lands a decisive blow on the Great Devourer. The beast roars in agony, its reign of terror finally coming to an end.

The ninja cheer as the Great Devourer is defeated. They thank Garmadon and Lloyd, acknowledging that their victory would not have been possible without them.

Despite their victory, the ninja know they can't let their guard down. With Garmadon's return and the Serpentine still at large, peace is yet to be restored to NINJAGO Island.

Lloyd makes a promise to continue his training, vowing to protect NINJAGO Island from any future threats. His journey as a ninja has truly begun.

Garmadon watches as the ninja celebrate their victory. He feels a strange sense of pride in his son but knows that his path is still shrouded in darkness.

Meanwhile, Pythor slithers away into the shadows, vowing revenge. He knows that the Serpentine will rise again and that next time, they will be unstoppable.

The ninja return to their training, more determined than ever. They know they must be ready for the challenges that lie ahead. Their journey is far from over.

As for NINJAGO Island, life slowly returns to normal. The citizens rebuild their homes and lives, hopeful for a peaceful future. But they know they can always rely on their ninja protectors.

And so, the story of the rise of the Great Devourer comes to a close. But the tale of the brave ninja, their young ally Lloyd, and the ever-looming shadow of Garmadon continues...