Kai grew up dreaming of becoming a blacksmith like his father. But that was before skeleton warriors ransacked his village and abducted his sister Nya. Now he's training to become a ninja master of spinjitzu in this Lego martial arts saga.

Long ago, the Four Golden Weapons of Spinjitzu were created by a great warrior who created Ninjago, the First Spinjitzu Master. When he passed away, his sons were tasked with protecting them but the older brother was consumed by evil and became Lord Garmadon, determined to use the weapons to reshape Ninjago in his own image. Sensei Wu was forced to banish his brother to the Underworld and hide the four weapons with dragons as guardians. However, Lord Garmadon has recruited an army of skeletons to find the map that will lead them to the four weapons. Sensei Wu needs Kai, Zane, Cole and Jay to use Spinjitzu and the Tornado of Creation to find the weapons first. Only then will the world be safe.

A solitary wanderer meets Kai, a young sword-maker, and his sister Nia in their small farming village right before a terrifying skeleton army arrives, ransacking their shop. The army takes a map hidden by their father years ago and Nia! The wanderer turns out to be Sensei Wu, an old friend of their father's. He promises to help Kai find his sister, but first Kai must become a ninja and master the art of spinjitzu. Kai begins his training and soon meets Sensei Wu's other ninja's, who realize they've all been recruited for very specific skill sets. Long ago, four weapons of spinjitzu were created by a great warrior. When he passed, his sons were tasked with protecting them. However, the older brother, Lord Garmadon, wanted to use the weapons for his own powerful and evil intents. Sensei Wu was forced to banish his brother to the Underworld and hide the four weapons with dragons as guardians.

A solitary wanderer meets Kai, a young sword-maker, and his sister Nia in their small farming village right before a terrifying skeleton army arrives, ransacking their shop. The army takes a map hidden by their father years ago and Nia! The wanderer turns out to be Sensei Wu, an old friend of their father's. He promises to help Kai find his sister, but first Kai must become a ninja and master the art of spinjitzu. Kai begins his training and soon meets Sensei Wu's other ninja's, who realize they've all been recruited for very specific skill sets. Long ago, four weapons of spinjitzu were created by a great warrior. When he passed, his sons were tasked with protecting them. However, the older brother, Lord Garmadon, wanted to use the weapons for his own powerful and evil intents. Sensei Wu was forced to banish his brother to the Underworld and hide the four weapons with dragons as guardians.

The ninjas are snapped out of their post-hero complacency when Lord Garmadon's son Lloyd shows up and tries to pick up where his father left off.

Back in training mode with the looming threat of Lloyd and the Hypnobrai, Zane wanders after a Falcon and lands himself in a heap of trouble.

Lloyd unlocks a second tribe, the Fangpyres, to help him regain control. The ninjas take action when the Fangpyres attack Jay's family's village.

After the Fangpyres join forces with the Hypnobrai, Lloyd awakens Pythor -- the last remaining snake of the Anacondrai tribe.

Lloyd moves in and tries to help out but just gets in the way. Pythor awakens the Venomari and the Constrictai, and an all-out snake war breaks out.

Pythor declares himself the destined leader who'll reawaken The Great Devourer, an ancient beast that can't be killed and will consume all of Ninjago.

When the four ninjas follow the mysterious falcon into the woods, they stumble upon a hidden workshop where Zane learns the secret about his past.

Jay and Nya must cut short their first date in Mega-Monster Amusement Park as the Serpentine are on their way to retrieve one of four fang blades.

The ninjas go undercover as a dance troupe and enter a talent contest in their quest to win the Blade Cup, where one of the fang blades is hidden.

The ninjas are suspicious when their archenemy Lord Garmadon moves in to help search for his missing son, but they realize they have to work together.

The ninjas try to infiltrate the Serpentines' inner sanctum and walk into a trap. When Lloyd's rescue mission fails, only Lord Garmadon can help.

The ninjas hastily journey to the lost city of Ouroboros to try to stop Pythor from awakening The Great Devourer, but it's a race against time.

Disaster threatens as the ninjas must fight to defeat the all-consuming Great Devourer in a desperate attempt to save Ninjago.

Just as the rebuilding effort in Ninjago begins, the four ninjas realize Lord Garmadon has forged the ninjas' lost Golden Weapons into a mega-weapon.

When Garmadon accidentally brings to life the ruthless Captain Soto and his pirates, it's up to the ninjas to stop them from plundering Ninjago City.

When our heroes are invited back to Darkly's Boarding School, they discover it's a trap set up by Lord Garmadon and his evil replica ninjas.

When the ninjas learn Dareth's Mojo Dojo is to be destroyed, they enter the annual NinjaBall Run to win a cash prize that will help save the dojo.

When the ninjas prevent Garmadon from using his mega-weapon to bring to life a fossilized monster, they're turned into kids and need Lloyd's help.

When Garmadon travels back in time to undo the past and rid the future of ninjas, the ninjas follow him and try to stop him using the Golden Weapons.

The ninjas face off with an exhibit of a stone samurai warrior that the toxic venom from the Great Devourer has brought to life.

The ninjas try to flee from the Stone Army, which has been brought to life by the Devourer's toxic venom. Garmadon tries to seize control of the army.

The ninjas, Lloyd, Sensei Wu and Misako journey to the Dark Island to find a Temple of Light that can restore the ninjas' elemental powers.

After fighting off the Stone Army, the ninjas arrive at the Temple of Light and harness their pure elemental powers, concentrating them onto Lloyd.

The ninjas try to return Garmadon's Helmet of Darkness to its perch at the Celestial Clock to prevent the final battle between Lloyd and his father.

Garmadon uses his new super-weapon to turn Jamanakai Village evil, unsettling the balance and allowing the spirit of the Overlord to possess his body.

A great darkness has fallen upon Ninjago as Garmadon's super-weapon has turned it evil, but the ninjas discover light is more powerful than dark.