Goldthwait Higginson Dorr (Tom Hanks), a charlatan professor has assembled a gang of "experts" for the heist of the century. The thieves: experts in explosions, tunneling, and muscle, and the critical "inside man." The base of operations: the root cellar of an unsuspecting, church-going little old lady named Mrs. Munson (Irma P. Hall). The ruse: the five need a place to practice their church music. The problem: it quickly becomes evident that Dorr's thieves lack the mental capacity to do the job. The bigger problem: they have all seriously underestimated their upstairs host. When Mrs. Munson stumbles onto their plot and threatens to notify the authorities, the felonious five decide to do her in. After all, how hard can it be to knock off one old lady?