Ben and Gwen wake up to Max banging a pipe at 12:00, and to their disappointment, they have to rotate the tires instead of hiking. Max still plans on rotating the tires and while he was distracted, his grandchildren sneak off and head for the waterfall.
Nearby, the Bugg Brothers had spoon-tunneled their way out of jail, Maurice having built a cloning device along the way. He later explains that he plans on using it to clone Diamondhead - when he had to explain the psychological effects on the target - so the duplicates can make a laser to blaze escape tunnels. They later set off to find Ben.
At a cliff, the Tennyson cousins marvel a waterfall before following some hikers to get closer. Unfortunately, Sydney sets loose large rolling rocks as part of Maurice's plan, but instead of Diamondhead as expected, Ben turned into Four Arms, rescuing the hiking couple before bashing the rocks to bits. As Todd chases a screaming Sally, Max turns up, congratulating the kids on the rescue and rewarding them by hiking instead of tire work, something they fist bump to.
Cursing he'd never thought Ben would be Four Arms, Maurice - with inspiration from Sydney - decides to use the Tetramand's arm count to his advantage. Unfortunately, Four Arms walked out of the sights at the last second, and Max was hit and cloned instead. Gwen and Four Arms immediately see the copies, and Maurice's anguished cry answers the former's question of the culprits. However, the Max clones carry Four Arms back to the campsite before he could attack the Bugg Brothers. Gwen quickly gives pursuit, and the Brothers follow them while Maurice's ray recharges.
The Maxes cause chaos at the site, and with the help of a tree, Gwen rescues Four Arms. He later gives off some puns related to the clones, and is relegated to sample study once he finished. He catches a clone and attempts an interrogation, but receives a wet willy when he denies it's request to pull his middle finger.
Gwen soon finds herding the clones to be a challenge, and after some difficulties, uses a chocolate bar to bait the clones so she can wrap them with the Rustbucket's cable. Unfortunately, the clones finish the chocolate before she could hook the loop, and her request for help was delayed by Four Arms dealing with his clone. A branch soon breaks under his weight, and his mad dash for support lead to him finally pulling the clone's finger and triggering a fart, the stink causing the Tetramand to cover his nose and inadvertently lets go of the branch. He later hooked the cable containing the clones for Gwen, and discussing their options, the Bugg Brothers made themselves known and Gwen sends Four Arms after them.
Maurice attempts to clone Four Arms and when he seemed to be too close, he decides to check if the scope was faulty... only to see the Tetramand right beside him. Just before he pounded the cockroach hybrid, Sydney leaped at Four Arms and sent the both of them tumbling down the tree, but ended up being victim to the Tetramand's throttling and demand on what they've done to Max. Maurice answers by firing the newly recharged ray, but just as he fires, the Omnitrix times out and Ben falls safely on the ground out of it's way, the beam hitting the Max clones instead.
Just as Sydney tries to attack Ben, three clones request him to pull their fingers. Ben covers his nose remembering his experience, just as Sydney suffers the consequences of his own. The Maxes later start patting him on the back, an escaping Ben noting they were on level with Stinkfly. Maurice, however was still determined and gives pursuit, but his next ray doubles a clone which catches him, destroys the ray and treats him like a kitten after duplicating.
Retreating to his cousin at the Rustbucket, they figure out how to return Max to normal, and a clone cannonball lets them figure out the method. Ben crashes down on them as Cannonbolt, and tosses a stick to Gwen when she has trouble. Not wanting to bash Max with a stick, she instead uses it to lure the clones with more chocolate and have them run into a wall. Cannonbolt corrals the final clones, and they hit each other on the head with sticks, reverting Max back to his old self. During the reunion, Maurice orders a grumbling Sydney to dig, but unfortunately, they were hit by Cannonbolt and subsequently rearrested. Maurice swears escape while Ben wishes he had the cloning device and list what he'd do with it until Gwen corrects his math. Max gives advice at the end along with a confusing phrase take makes his grandchildren wonder if they missed a clone. They did, but it took care of itself and tumbled down a hill before puffing into dust.