A rich family, father, mother, two daughters, a son-in-law and two children are on holiday at the family house on a small island when a handsome stranger arrives. He is the friend from schooldays of the son of the family whose arrival is expected at any time to set off fireworks on July 14th. The stranger, Boris, rapidly insinuates hiself into the family circle with both daughters flirting with him, the uunmarried one possibly going further, thre mother all but treating him as the absent son as does the father. The only person not taken with him is the son-in-law who sees him as an usurper. Joncour builds up the hold the stranger has and the
underlying tension in spare laconic language until the climax when the two men go to the mainland to collect the fireworks with Boris deliberately tormenting and belittling the son-in-law. In the mainland town, however, the son appears and he and the son-in-law return to the island alone saying that Boris had other plans. Later that evening, he turns up. The scene shifts to the mainland where the local ironmonger who had been storing the fireworks hears an explosion from the island which he thinks is the fireworks going off early though there is no sign of them - and that was the only explosion of the evenng....This leavesthe reader to decide what the explosion was using the earlier exposition of the internal family relationships, both good and bad, to provide clues. At the beginning I could see a certain similarity to the Ripley novels of Patricia Highsmith but the book turned out to be more about the effect an intruder can have on a family even though the book is a prize-winning noir. Not certain if I would read more of this author.