Good Used. It was at Styles that Hercule Poirot first met Arthur Hastings. Now Poirot summons Hastings again for what Poirot knows will be his last case - and perhaps one of his most intriguing ones. There have been five unrelated murders. In each case there is only one obvious murderer, but one person appears to have known all five victims. Poirot is determined to prevent the next murder..