Set in the San Francisco Bay area in the late 1950s, Humpty Dumpty in Oakland is a tragicomedy of misunderstandings among used car dealers and real-estate salesmen: the small-time, struggling individuals for whom Philip K. Dick always reserved his greatest sympathy.

Jim Fergesson, an elderly garage owner with a heart condition, is about to sell up and retire; Al Miller is a somewhat feckless mechanic who sublets part of Jim's lot and finds his livelihood threatened by the decision to sell; Chris Harman is a record company owner who for years has relied on Fergesson to maintain his cars. When Harman hears of Fergesson's impending retirement he tips him off to what he says is a cast-iron business proposition: a development in nearby Marin County with an opening for a garage. Al Miller, though, is convinced that Harman is a crook, out to fleece Fergesson of his life's savings. As much as he resents Fergesson he can't bear to see that happen and - denying to himself all the time what he is doing - he sets out to thwart Harman.