9Agatha Christie wrote this novel in 1923: it is the second novel in the Poirot series, after The Mysterious Affair at Styles, the 1920 debut in which Poirot appeared, and the third in general, because a year earlier, in 1922, "The Secret Adversary" was released, in which the couple Tommy & Tuppence appeared.It is one of the novels that I liked most, of the many written by Agatha Christie. There is one reason: it is a fresh, sparkling text, full of pitfalls, false tracks, true clues and false clues, and with a pyrotechnic ending.A truly magnificent novel, with a young Poirot, and in full mental health above all (to be enjoyed, his lucubrations on his famous "gray cells"), is a continuous tourbillon of situations, some of them almost at the limit of the paradoxical, if not of the grotesque, though being dramatic. There is no way how Christie gave her imagination so much, inventing a plot, so tangled and yet so linear: there are two false solutions, obviously indicating two false killers.THE PLOTInvited to travel to France to protect a man threatened by an unknown danger, the famous Hercule Poirot on his arrival has a depressing surprise: his client has already been murdered by a couple of mysterious foreigners. In charge of investigating the crime, the Belgian detective discovers, together with faithful captain Hastings, that the crime was carried out following the same method as a murder committed many years before and that the victim, while ardently loving his wife, was linked to a woman fascinating and enigmatic.