Walter Krattwinkel, who runs Bochum's most popular curry sausage snack-bar, is found fatally stabbed inside at night. To son and heir Sasha's horror, the top-secret family sauce recipe on which their success depends is missing from the safe, and he never got to read it. Heldt tricks first Grün, then Ellen into helping him reconstruct the recipe from a bit Ahmed never got round savoring, but even the crime lab's analysis of ingredients doesn't get them near enough. Meanw grump Walter made potential enemies on a daily basis so Heldt goes the extra mile to check them out, even if that means going undercover with the despised industrial competitor, who bid to buy out Walter and plotted with the sausages supplier, who wanted out of an exclusivity contract.
—KGF Vissers