O'Hara poses as a drifter and joins a small band of flower children in the desert. He must undercover the location in a nearby city where they planted a bomb and are extorting $200,000 from a publisher.
When a professional sports bettor's wife tells O'Hara her husband might be a tax evader he investigates. He finds a world filled with people on the make and who don't brag about their winnings.
While probing for evidence of Federal income tax violations Jim O'Hara runs afoul of a small town power broker and becomes the target of veiled threats against his life by the citizens of a small town.
O'Hara accompanies a diamond broker (Joseph Wiseman) to Africa to investigate his claim that he is a pawn in a smuggling scheme, however he has a suspicion that he is being set up.
Jessica Tandy stars as an elderly but peppery former Parisian artist's model who assists O'Hara in building his case of income tax evasion against a racketeer specializing in art swindles.
The ex-wife of a nightclub comic (Godfrey Cambridge) reports to O'Hara that her husband has arranged to deliver a bribe to an Internal Revenue Service man in return for the cancellation pf a scheduled IRS audit of his income.
O'Hara is approached by Laura Alpin who's the wife of mob racketeer Mike. Fed up with her husband's cheating on her she's ready to give evidence of his tax evasion. Mike decides to take measures to prevent his probable prison life.
