During the Mud Fest event, Blaze and AJ meet Gasquatch, a friendly forest creature who enjoys mud more than anything. The two work together to help him get to Mud Fest so he can enjoy the fun and even befriend a petrified Crusher who thinks he's a scary monster.
Blaze and AJ begin by sliding down a mud slide while already looking super muddy. They greet the viewers and explain why - today is Mud Fest, and their friends are here for a giant mud party. There are slides, games, and even a giant mountain, all covered in mud. They then join Gabby, Starla, Zeg, Stripes and Darington to play a game of Mud Ball.
Elsewhere, Crusher and Pickle are also attending Mud Fest, the former of whom despises mud a lot. Pickle thinks this is because he never tried playing in the mud before and invites him to join in the festivities, but he refuses and in turn, accidentally sends the ball to the Mud Ball game into the forest. Blaze and AJ promise to get it back, and Pickle sends Crusher as well since he was the one who lost it in the first place.
The trucks search the forest and Blaze finds the ball, but when they are about to head back, the mud puddle that Blaze landed in somehow rises and clears away to reveal a strange creature who scares Crusher away, thinking he's a mud monster. The creature introduces himself as Gasquatch, and says he lives in the forest where he doesn't get any visitors, but has mud to play in which he loves. When Blaze invites him to come back to Mud Fest with them, he is overjoyed and accepts. They set off as Blaze sings Hit The Road.
Blaze and Gasquatch eventually come to a snowy landscape, and slip on the icy terrain when all of a sudden, Gasquatch lets out a loud and booming sneeze. He reveals he sneezed because there was a bush of purple truckberries nearby; whenever he smells them, he sneezes loud and long. He unleashes another sneeze which causes a big rock to slide down a mountain from behind and chase them across the ice.
Since the rock is big and heavy, it is unable for it to stop moving due to having inertia. Blaze tries to stop it, but he can't push hard enough, as does Gasquatch, but when they push it together, they manage to stop it just in time before they fall off a cliff. They go on their way as they sing the Inertia song.
Back at Mud Fest, Crusher retreats from the forest and bolts right into a tent. He informs Pickle he's hiding from the "mud monster" which excites Pickle a little, but denies that he's scary as he squeezes into the tent to hide with him, but there isn't enough room and accidentally collapses it.
Meanwhile, Blaze and Gasquatch are almost at Mud Fest; all they have to do is cross a river to a dock. Gasquatch decides to use a raft to get across, but he sees another bush of truckberries and unleashes another big sneeze which causes the raft he's on to move down the river itself and not stop. Blaze turns into a tugboat so he can push the raft hard enough, but when he gets to Gasquatch, he sees the raft heading for sharp branches which will pop it. He manages to push with enough force with help from the viewer, and gets him to the dock safe and sound. They eventually spot Mud Fest in the distance, which gets Gasquatch excited.
Pickle finds Crusher who is hiding on top of Mud Mountain so the "mud monster" won't get him, only to spot a storm cloud and freak out, getting his tire stuck in the mud in the process. Gasquatch arrives to help and has a plan: he can blow the storm cloud away with one of his sneezes. To do such, he needs a whole bunch of truckberries from the forest which will make him sneeze his biggest sneeze ever.
Blaze hurries back into the forest to collect the truckberries, and he finds enough with help from the viewer to fill the jar he uses. Since the storm cloud is almost at Mud Mountain, he uses Blazing Speed to get back fast enough. By now, Gasquatch has climbed up to Crusher who is scared to see him, and Blaze gives him the truckberries which makes him emit a sneeze so loud, it sends the storm cloud away.
Crusher is confused and thought Gasquatch was a monster all this time, but Gasquatch isn't a monster at all, he just loves mud, and Crusher admits he should've gotten to know him better and Gasquatch makes him his friend. He helps Crusher back down and Blaze and AJ introduce him to the other trucks before he jumps into a mud puddle with them. Pickle then does a big splash which really gets Crusher dirty, and Gasquatch thanks Blaze and AJ for bringing him to Mud Fest before showing off his mud belly flop, ending the episode.