The episode starts off at the park where Greg is finishing playing frisbee with a couple of friends. He meets up with Connor and Amaya, who are practicing for their retreat on Mystery Mountain. An Yu is going to teach them tonight how to become stronger using their minds. However, since Greg knows he already has his Super Gekko Muscles as Gekko to become strong, he volunteers to stay behind and protect HQ. That night, Catboy and Owlette prepare to leave for Mystery Mountain when Armadylan comes rolling in. Hearing about guard duty, he decides to stay with Gekko and help protect HQ as well. Gekko agrees, as PJ Robot will need the help he can get from the two strongest heroes. That being said, Catboy and Owlette head off.
PJ Robot checks the PJ Picture Player: there are no signs of any villains around and causing trouble, much to Armadylan’s disappointment. To entertain him, Gekko shares that whenever he’s bored, he exercises his muscles to stay ready for action. Armadylan challenges him to lift the Cat-Car, and the two do so, Gekko with two hands, Armadylan with one. Armadylan then comes up with an idea: they should do a competition to see who’s power is the strongest - Gekko’s Super Gekko Muscles or Armadylan’s Thunder Thump. Gekko accepts, and suggests they should do this contest outside.
The boys head to town and gather up a couple of vehicles. Gekko stacks up multiple cars and lifts them up, while Armadylan grabs a bus and lifts it up. Once he puts it down, though, it rolls towards one of the buildings. Gekko stops it from crashing and warns Armadylan what just happened, to which he reassures him that it was just a way to test their strong reflexes. The two then go over to the museum to take their strength competition to the next level. Using their powers, Armadylan lifts the building one time, and Gekko lifts the building three times.
The next few challenges follow up as they find a couple of boulders to do some tricks on and then throw them as far as they could. After knocking down a tree, the boys run off to another part of the town and find a couple of wrecking balls. The two juggle them, and after a few moments, despite a misstep, they catch them, and two of them land on a couple of parked cars.
Meanwhile at Mystery Mountain, Catboy and Owlette meet An Yu at the pagoda, who leads them inside to show them an old relic: the Thinking Stone. The three sit in a circle, and An Yu explains that to use the stone’s power, they must concentrate. This is how the heroes can become strong, both in body and mind. She demonstrates by using a miniature gong. She spins the object, concentrates for a few moments, and it slows down. Catboy and Owlette give it a try with her, and they realize that the power gets stronger as they focus together. They try it on a couple of spinning vases, and the same result happens.
Back in the town, Gekko stops Armadylan from using his Tornado Thunder Roll. Armadylan claims that he is still the strongest, though, and can prove it by lifting up a dinosaur. Gekko tells him that they are extinct, so Armadylan suggests lifting up the whole planet, although it involves going into space and finding someplace to stand on. After thinking for a few moments, they look at HQ and decide that they can use the structure as the final test to see who is the strongest. They race over and fight over who gets to go first to lift the totem and hold it as long as they could. However, its movement forces PJ Robot to accidentally hit HQ’s rocket function. HQ lifts off, and starts spinning out of control.
As Catboy, Owlette, and An Yu continue their meditation, An Yu’s staff senses trouble in the city. Catboy and Owlette confirm this as they hear PJ Robot’s voice through their communicators, indicating that he is in trouble. The three run back through the Mystery Mountain portal and see the destruction left behind, plus HQ flying erratically. Gekko and Armadylan catch up with them and explain the mess they caused was because they were having a super muscle contest. Owlette tries to save PJ Robot as he is inside, but HQ is spinning too fast. However, the group has the Thinking Stone; if they hold it and concentrate, it can slow the structure down. It has been done with small objects, though, and not big ones, so the group has to concentrate together for the stone to work its power.
The five kids put their hands on the relic together and start concentrating, but nothing is happening. Armadylan apologizes, thinking about a turkey sandwich with lots of pickles, and resumes concentrating with the group. This time, the stone uses its power and slows down HQ, but it starts to break due to its size. This gives Gekko and Armadylan a chance to stop the structure by pushing against its wings. Once they stop it, Gekko enters the totem and shuts down its rocket function. It returns to its normal place, and Gekko comes out with PJ Robot unharmed.
Everyone reunites, and Catboy comments how Gekko and Armadylan really did hold HQ down. Gekko replies that they all did it together, both with their bodies and with their minds. An Yu adds on that although the Thinking Stone is now broken, everyone has learned its power and the importance of staying calm and focused to be a hero. Gekko and Armadylan still have to clean up the mess they made from the contest, but they decide to do that by working together. With that, everyone proclaims the PJ Masks’ signature victory phrase, and the episode ends.
Work together and don't be overly competitive.
Being competitive makes things worse.
This is the first episode in which no villains are present.
This is also the seventh time all the villains are absent counting shorts.