Before a big one-on-one race at Dragon Island, Crusher cheats and separates Blaze from AJ, trapping him in a cave. AJ has to work hard to reunite with his friend and get back to the race.
On an island called Dragon Island, Bump Bumperman announces the start of a race called the Dragon Island Duel, where two Monster Machines will race through the jungle to the top of Mount Dragon. Crusher is the first participant, though no one but Pickle cheers him. But they do cheer for Blaze, the second participant, who has AJ with him.
Blaze and AJ don't think Crusher is going to win the race, because Blaze has something Crusher doesn't: AJ as his best friend and partner, and nothing beats best friends, as they say. As they get ready for the race, Pickle shows Crusher some pictures he took of he and Blaze racing; coincedentally, every picture shows him cheating to stop Blaze, followed by Blaze getting around the cheat and winning. Crusher is annoyed that Blaze always wins and that his cheating never works, so Pickle suggests he should try racing fair for a change. Crusher denies and decides to try his biggest cheat ever.
Constructing a robo-bouncy ball, Blaze gets trapped inside it and gets carried away into a faraway cave. By the time he stops and escapes, he attempts to get back to the race but the result of the bouncing causes a rock slide to block the cave entrance, and he cannot push the rocks as they're too heavy. Since Blaze is trapped, he cannot race, and Crusher is triumphant until AJ sets off to rescue him which Crusher denies.
AJ hurries through the jungle as Let's Blaze plays, then comes to a deep river which is a long way down. Spotting some slippery slides, he does an investigation to see which one he should take. With the viewer's help, he uses coconuts to pick the right slide and successfully makes it across. He then gets a call from Blaze saying he cannot push the rocks away as they're too big. AJ reminds him not to worry as he's coming to help.
Back at the start, Crusher is reminded by Pickle that AJ is going to save Blaze and how far he made it. Crusher is shocked and sends out some laser bugs to stop him, which seem like ordinary bugs, but have strong laser beams that can cut through almost anything.
Encountering the bugs, AJ does another investigation to see what lasers can't cut through, but he is proven wrong when the branch and steel pipe he finds are cut. So he decides to try something different, bounce the laser beams away. Finding a mirror, his investigation is successful, and when he turns it, the laser beam destroys the bug. He destroys the others with help from the viewer and spots the cave where Blaze is trapped. He heads for the cave while singing Let's Investigate.
Finally reaching the cave, AJ spots the blocked entrance which he can't get through, so he finds a small hole at the top which he can fit through. He slides down the hole and reunites with Blaze inside, and assists him in finding a way to break through the rocks. Blaze finds some tools behind a rock, one of which can break rocks. The saw and hammer don't work, but the drill does, so Blaze turns into a roadheader tunneling machine and successfully breaks through the rocks, freeing himself. He then hears the race fanfare which is the signal that the race is about to start, so AJ gets on him and they hurry back before it's too late.
Back at the start, Bump announces it's time to start the Dragon Island Duel, but since Blaze and AJ are not back yet, Crusher will have to race by himself to his delight. However, his celebration is cut short when Blaze makes his grand return, and is back just in time.
The race begins, and the two trucks race each other around the island with different consequences, Blaze getting through easily while Crusher hesitates. By the time they get to Mount Dragon, Crusher is far in the lead and is determined not to lose, so he cheats one last time and knocks over a rock to slow down Blaze. Fortunately, Blaze knows he and AJ can still beat Crusher and unleashes his Blazing Speed, passing Crusher and winning the Dragon Island Duel together.
At the bottom of the mountain, Crusher wallows over yet another loss, only to be blasted by Mount Dragon's smoke. When he gets blasted a third time, he crashes and gets covered in coconuts, and Pickle takes a picture of him as the episode ends.