Mickey takes Minnie out on a vacation to visit Nature's Wonderland and the Rainbow Caverns, only to find "a big thundering mountain" now stands in its place. Not deterred, Mickey takes Minnie into an abandoned mine shaft to try and find the Rainbow Caverns, only to find that Mickey's map is merely a souvenir not meant for actual navigation and they accidentally board a runaway mine train. After careening through some caves, smashing into Balancing Rock Canyon, the Devil's Paintpots and the Old Unfaithful Geyser, the train ends up being sent back into the mountain. As the train tracks start to fall apart behind them, Mickey ends up burning his souvenir map for an extra speed boost. The train finally stops in front of a dynamite stockpile, which is set off by sparks kicked up by the train. The force of the explosion sends Mickey and Minnie down into the Rainbow Caverns, where they take a romantic ride on what's left of their train.
- The episode is an extended homage to the extinct attraction Mine Train Through Nature's Wonderland and the attraction that replaced it, Big Thunder Mountain Railroad.
- The attraction poster for the Grand Canyon Diorama is recreated in one shot.
- A drawing of Walt Disney appears on Mickey's map, inspired by the Disneyland map posters sold at the park.
- The background art of the title card is based on the title cards from Walt Disney's True-Life Adventures series.
- The melody of the song that Mickey and Minnie sing throughout the episode comes from Pinocchio's "Little Wooden Head" and "When You Wish Upon a Star".