Marva Munson is a spry, elderly woman who is looking for a tenant for the spare room in her house. Goldthwait H. Dorr moves in and gains Munson's permission to use the basement for rehearsals with his "medieval music ensemble." Dorr is masterminding the robbery of a riverboat casino, and the fellow musicians in his ensemble are actually the crew he's assembled to pull off the job. Despite their best efforts, Munson finds out about their scheme and Dorr decides the best solution is to silence her permanently.