Oswald and a big beagle are at a cinema watching a documentary. The documentary tells about explorers who travel place to place in their hot air balloons. Oswald is amazed by the adventures of the explorers, and therefore decides become an explorer too.
One day at a fairground, a large crowd gathers to see Oswald take off in his balloon. The balloon is a large hot water bottle and the carriage is a metal stove (with switches inside). Oswald invites the big beagle, who is in the crowd, to join him.
The big beagle, at first, declines the invitation before he shakes hands with his little friend, and releases the balloon. But as the balloon rises and one of its anchors snags away his pants, the big beagle changes his mind. He would spend the entire ride on the anchor.
Oswald's balloon rapidly ascend into the heavens. They go so fast and so high that they even reach space. Their voyage ends when they land on the planet Mars. Unfortunately for them, their balloon is wreck, and the two are left wondering if they would ever get back. They begin walking on the rocky Martian surface. On the way, they see a giant sipping soup and gobbling explosives. Because of the giant's hostile nature, Oswald and the big beagle try to flee, only to unknowingly run into the bore of a huge cannon. The cannon shoots them airborne and they land in the giant's soup bowl.
The giant is surprised to see the two visitors in his bowl. Nevertheless, he becomes obliged to gobble them as he scoops up Oswald and the big beagle with his spoon. Suddenly the giant decides to delay eating his victims. He then puts Oswald and the big beagle in a large salt shaker and then chooses to have some music played by walking guns.
While the giant is enjoying his tunes, Oswald and the big beagle rock the salt shaker back and forth until they turn it upside down. By putting their legs through the shaker's holes, they are able run. As they make their move, they collided into a large pitcher, thus shattering the shaker and freeing them.
In no time, the giant notices their escape and tosses large forks on the table to entrap them. The giant then holds Oswald and the big beagle in separate hands, and their doom seem pretty much sealed.
It turns out what Oswald and his buddy are experiencing is merely a bad dream as they are actually dozing at the cinema. The cinema's janitor comes in, waking and telling them the film is over, and all the audiences had left. Oswald and the big beagle quickly get up and start to leave hysterically.