Sis discovers an invention to make gunpowder harmless and sets out for the city to interest "the world's greatest inventor" in her project to end all wars. Louie Cheesecake, who believes he is "the world's greatest inventor," escapes from Buggeville and finds his way to the laboratory of the real inventor while that personage is out. Of course, Louie welcomes Sis' invention with open arms and, securing a keg of gun-powder, they prepare for an experiment. The real inventor arrives in time to get mixed up in a train of laughable and exciting incidents which end when Sis and Louie make their experiment and find themselves whirling through the air. Back in Blueberry Gap, swathed in bandages and carrying a crutch, Sis swears off inventing.
—Moving Picture World synopsis