Peppard played Thomas Banacek, a suave, Polish-American freelance investigator based in Boston, who solved seemingly impossible thefts (see locked room mystery). He then collected from the insurance companies 10% of the insured value of the recovered property. One of Banacek's verbal signatures was the quotation of strangely worded yet curiously cogent "Polish" proverbs such as:
* If you're not sure that it's potato borscht, there could be orphans working in the mines. * Though the hippopotamus has no sting, the wise man would prefer to be sat upon by the bee. * A truly wise man never plays leapfrog with a unicorn. * If a wolf is after your sleigh throw him a raisin cookie—but don't stop to bake him a cake. * Just because the cat has her kittens in the oven doesn't make them biscuits.
Another recurring gag was for other characters to mispronounce his name, often (particularly in the case of rivals) deliberately. The name "Banaczek" (as pronounced in the show) is actually very rare in Poland. The closest Polish names in common use are Banaszak (bah-NAH-shack) and Banasik (bah-NAH-sheek). In fact, Banáček is a Czech surname.