Another Lieutenant French story, in which this able State trooper detective does his stuff. A pretty good yarn, with the setting an estate part of which has been rented to summer boarders who do not wish to leave when their time is up. But there is an inexplicable death -- then a second, and Detective French saves a third. A polygraph, sort of up-to-date lie detector, helps confirm his suspicions, and he sets a trap into which his suspect neatly falls.