Trama

Lloyd discovers that there are a group of bandits that follow Lord Garmadon even though Garmadon is dead

A group of bandits known as the Sons of Garmadon steal a powerful relic from Cyrus Borg, known as the Mask of Deception. Now Lloyd needs to re-unite the team in order to stop the Sons of Garmadon from gathering all three Oni Masks and resurrecting Lord Garmadon in his evil form.—Bilis

One year has passed since Krux, Acronix, and Master Wu were all lost in time. During a celebration in downtown Ninjago City, six masked members of the Sons of Garmadon infiltrate Borg Tower and steal the Oni Mask of Vengeance. While leaving, they are confronted by Lloyd, who fights and overpowers most of them. However, Mr. E manages to escape with the Oni Mask, with Lloyd telling P.I.X.A.L. it was time to get the crew back together.

Meanwhile, the other Ninja are on various missions around Ninjago. Nya is dealing with a group of samurais in a valley, Cole and Jay are searching for Master Wu at an ancient temple, and Kai and Zane are battling the Mechanic.

Once the Ninja team get back together, Hutchins appears and tells the Ninja about the Oni Masks. The Ninja are then told that the Royal Palace was holding the Oni Mask of Deception. Hutchins fears the Sons of Garmadon will try to take the mask during a speech the emperor of Ninjago will give tomorrow, and asks the Ninja to help protect it, and the Ninja accept.

While they are guarding the palace outside during the Emperor of Ninjago's speech, Lloyd notices Harumi. The Ninja then think the palace is being attacked, but it is a false alarm. The Ninja are then invited by the princess to stay at the palace because the Royal Family is targeted since they have one of the Oni Masks. They accept the invitation.

Hutchins takes the Ninja on a tour of the palace after they agree to protect the Royal Family. They meet the family who greet them in a kind manner before Harumi herself meets them, stating she was fans of all of them, even changing Nya's cynical attitude to a happy one. They visit the royal buffet and Hutchins states that they have access to eat anything like assorted fruits, assorted vegetables, scones and cake. Jay then states that Cole has "gave up sweets" due to the fact that Master Wu is gone. Proceeding on the tour, Hutchins tells the Ninja there are many secret passages in the palace that only the Royal Family know. After hearing this, Kai starts pulling books off the shelves, trying to find one of the passages. The Ninja are now lead into the main room where the Oni Mask of Deception is being held. Hutchins starts to explain about the mask, but while he is, Lloyd sneaks off to a room to find Harumi doing her makeup. Harumi notices Lloyd through her mirror and she quickly hides her face. Lloyd backs away awkwardly and rejoins the group.

During the night, all the Ninja are on guard. Kai and Nya are outside the castle when they notice Hutchins suspiciously walking away from the palace. He then notices them and walks back inside. Jay, Cole and Zane are in the royal buffet room. Jay is trying to convince Cole to eat some cake but Cole refuses. Cole then proceeds to tell Zane what a "party pooper" is. Meanwhile, Lloyd looks at the Mask of Deception, but after calling out for Harumi, he notices she is missing.