Masters Never Quit is the twelfth episode of the thirteenth season of Ninjago and the 156th episode overall. It aired on July 20, 2020, in Australia. It aired in the US on October 18, 2020, paired up with "Grief-Bringer".
Pursued by a magma monster, Cole, Princess Vania, Wu & the Lowly arrive at a mysterious temple deep in Shintaro Mountain, a temple which was once a training ground for Earth Elementals including Cole's own mother, Lilly!
Cartoon Network Asia: Cole, Princess Vania, Master Wu and the Lowly arrive at an ancient abandoned temple. Wu realizes it is The Heart Of the Mountain.
The Upply, Cole, Vania, and Wu are running away from the Lava Monster. They find some old mine carts and ride the carts to escape the Lava Monster. After a roller-coaster type ride, they finally crash but are safe from danger.
Everyone else is confused about where they are, but Cole has a strong presence. Suddenly, the torches engine with fire and Wu figures out they are at the Heart of the Mountain. Wu explains the Heart of the Mountain is a legendary temple of the Masters of Earth. Some thought it was hidden in the mountains of Shintaro, but nobody could find it. Vania also explains there's something precious inside the temple, and Plundar thinks there is treasure inside, but Wu explains the teaching of the Spinjitzu Burst can be found. Wu informs Cole that Lilly tried to learn the ancient martial art, but she could not succeed.
Korgran and Plundar try to open the immense doors but fail. Wu explains the Master of Earth is the only one who can open the doors, so Cole tries and his powers absorb the doors allowing it to open. They soon begin to explore and in the middle of the statue, they discover the previous Elemental Master of Earth, Lilly. Cole touches the statue and the entire temple is ignited with light. Fungus and Adam then discover an old mech that catches everyone's attention. Unlike any other mech, Wu realizes it's made of stone.
While Cole is reading the statue about Lilly, the center of the floor changes color and the Elemental Energy depicts the patterns on the ground. Cole realizes his mother actually used Spinjitzu Burst. Vania then tells Cole to attempt the Spinjitzu Burst, but Cole is hesitant to attempt. He believes the Blades of Deliverance allowed for Lilly to perform the burst, but Wu still wants Cole to try.
Cole attempts to focus, but he gets nowhere. Wu advises Cole to open his mind knowing only an Elemental Master of Earth could perform the Spinjitzu Burst. Cole tries again, but only performs regular Spinjitzu. He gets frustrated at himself and the mountain and bangs his hands, causing the mountain to rumble like thunder.
After the tumultuous sound, Fungus performs some magic to see how it affected everyone else. They discover the rest of the ninja running away from Grief-Bringer. Cole realizes they have to help, but Wu comments about the Spinjitzu Burst being the only way to save everyone. However, Cole is frustrated he can't perform the burst and walks away from the group. Vania then criticizes Wu for not helping him enough, but Wu believes he is no longer needed, as Cole has many accomplishments without Wu.
Cole is outside the temple, so Wu heads outside to meet him. He instructs Cole to get up, but Cole complains about trying many times. Wu then admits neglecting his role as Master and promises to never quit his job.
The episode's name is similar to a line frequently said by the ninja, "Ninja never quit."
Similarly, Master Wu's line "They would never quit on us and we will never quit on them," sounds similar to when Cole said "Wu would never quit on us, and we're not quitting on him," in "The Mask of Deception".
This is the first time Wu has announced an episode title since "A Cold Goodbye."