When two women are “accidentally” killed by gas leaks, Sergeant Studer investigates the thinly disguised double murder in Bern and Basel. The trail leads to a geologist dead from a tropical fever in a Moroccan Foreign Legion post and a murky oil deal involving rapacious politicians and their henchmen. With the help of a hashish-induced dream and the common sense of his stay-at-home wife, Studer solves the multiple riddles on offer. But assigning guilt remains an elusive affair.