Mary Ann Jackson and Bobby "Wheezer" Hutchins are the children of a widowed inventor who are forced to endure the cruelties of their stepmother and stepsister. The kids get even by rigging a few clever contraptions of their own. In the end the father sells a patent worth millions. Before that, the Our Gang kids bring out out the old "alum" gag, along with several other tried-and-true comedy bits.