The episode starts with Zane, underwater, beating the record for the longest time underwater. The ninja are happy at Zane's record and go to Sensei Wu to find out if they unlocked their full potential. After finding him, Sensei is disturbed. The Ninja explain that they are sure they have reached their full potential. However, Sensei Wu corrects them, saying they have gotten their full physical potential, but they have not reached their full potential, or true potential.
Sensei Wu begins to relate a story about his childhood, how his brother, Lord Garmadon, was nice and friendly. He told them they were the best of friends. One day, while they were practicing their skills, Wu lost his katana, and his older brother sought to find it, knowing their dad would be mad. He finds the sword after clambering over the wall, however, he is bitten by a snake. "A legendary snake..." Sensei Wu comments, as he tells the ninja that the snake biting Garmadon made him develop an increasingly darker nature.
He then tells them that he is to go on a journey. The ninja are taken aback, yet they decide to go to the village to post signs about Lloyd's disappearance. As Zane is posting signs, he sees the Falcon, the same one that guided him to the Destiny's Bounty, and Lloyd's fort. He and the ninja follow it. Zane follows it obsessively, oblivious to all but the falcon. A montage shows of the ninja, going through all sorts of terrain to reach the falcon's destination. As they come upon a frosted forest, the others are too tired, yet, Zane goes forward. As he follows it, the falcon suddenly drops to the snowy ground.
Zane picks it up, and finds it is merely a robot, or android. Zane is then disturbed by a robot, though quickly destroys it to find the same symbol on the robot and the falcon. Zane proceeds into a hollow tree, with a spiral stairs that leads down. He finds an assortment of many things. He then finds a blueprint with a figure on it. He drops to his knees, yelling in disbelief. The other ninja, seeing the hollow tree, find Zane, still on his knees. They inquire why he is at his position, when Zane tells them he is a machine. He shows them his stomach, which is hollow, with an assortment of cords and cables. He tells them that he is a robot, nothing less, or more. Zane then asks if he can be left alone. The ninja agree, and follow out of the room.
Soon after, Kai, Jay, and Cole are shocked and reproachful about Zane's secret. However, they come upon Treehorns, which try to kill them. They dodge their attacks, but are unable to defeat them, until Zane comes. Zane leads the ninja into battle, and they defeat every one of them, but things take a turn for the worse when the Queen arrives. Suddenly, Zane, by unlocking his heart, releases his full potential on the Queen, who joins her fellow Treehorns in retreat. The ninjas note that Zane has reached his full potential. Very happy, Zane, Kai, Jay, and Cole, begin the long trek back to the Destiny's Bounty.
Meanwhile, Pythor is still desperately trying to reunite the snake tribes. He has been attempting to solve a riddle: "When five fangs unite as one, the path toward the Devourer has begun." The other leaders begin to doubt Pythor, saying that snakes will begin to ask questions. Just then, Acidicus and Skalidor get in a tussle with one other, and their staffs are relinquished from them. The venom from the staffs drips onto the floor, giving Pythor an idea. He gathers all of the staffs and puts them in a leaning formation on the table, sliding a scrap of paper underneath. The venom from the five Snake Staffs drips onto the paper, creating a map showing the locations of the four Silver Fangblades. Having solved the riddle, Pythor and the others rejoice.
Meanwhile, Sensei Wu is on top of one of the Mountains of Impossible Height. A vortex then erupts, and he is dissolved into it. He reappears in the another dimension, where he is greeted by his twisted brother, Lord Garmadon, who then precedes to laugh wickedly.
