Investigator Lunin again receives a case that can rightfully be classified as hopeless. A successful businessman with his wife and daughter went on a long trip around the country by car. We stopped for a picnic in a picturesque place. They were attacked by a group of unknown people. The wife and daughter died, the husband is in intensive care. When I woke up, I could not give a single detail. No traces, no evidence... Seemingly clumsy, Lunin begins to search for any clues, but every thread breaks: possible witnesses die one after another. True, one of them casually mentioned a minor circumstance that seemed strange to the meticulous investigator...