Here's what tvguide says:

Abominable comedy has Amsterdam and Marie (also cast is Deacon, another refugee from "The Dick Van Dyke Show") as a short-order cook and a waitress, respectively, in a greasy-spoon diner. One day their incompetence gets them fired, so they go to help a friend (Jones) run a bookstore she's inherited. Russian spies mistake Amsterdam for a defecting cosmonaut, and soon spies, counterspies, federal agents, and local policemen are chasing our inept heroes and each other up and down the rows of books. Making matters worse are a couple of bank robbers using the store as a base to tunnel into the vault next door. One of the gags is that the head spy, "Mr. Big," is a midget. It's all downhill from there