A celebrated professor of chemistry discovers two wonderful powders. When combined, they form a product which reverses the well-known law of gravity and sets all objects that it touches free to roam in space. The professor's joy over the discovery of this reverse gravity is so great that he starts out to tell the world. While waving the two papers containing the powders over his head, a little of each is accidentally spilled on him. Before he can realize what is happening the professor is sailing out of the window and through the clouds, on his way to the planet Mars. Arriving there upside-down he scrambles along the under surface of the planet and finally finds himself in a dense wood of trees, which are of enormous size. The upper halves of the trees are semi-human monsters which reach out long arms to seize him as he runs between their trunks. Escaping this peril, he climbs upon a ledge of rocks. Jumping off a promontory, he lands upon what, when the rocks wake up, proves to be the lip of a half-human Martian. We see the creature open his eyes and lips, and from the latter issues a cloud of steam with such force that the professor is blown high in the air. The Martian watches his descent and catches the professor on his gigantic hand. The professor looks up at the enormous face above him and sinks on his knees. Again the Martian blows his breath upon him, and slowly the professor congeals until he is a snowball, which the Martian places over the fire. The ball swells and swells until it explodes, and the professor is again blown off into space, but this time in the direction of Mother Earth. We see him falling headlong and turning over and over in his homeward flight, until he drops into his laboratory again; and having had quite enough of reverse gravity, the professor casts the powders in rage upon the floor. The result is that one side of the floor and the same side of the room rise until the professor slides down its perpendicular edge; and the last that is seen of him the room is spinning him around at a dizzy pace.