A late-night murder of a diamond merchant's veteran employee in London's Hatton Gardens has Scotland Yard calling on Inspector French to investigate. When French gets there he finds not only the victim but missing diamonds and money from an open safe. There are meager clues as the Inspector follows a trail to mainland Europe and back. There are many false clues and several suspects with much of the searching leading to nothing but dead ends. We can listen as French sorts it all out, finding the missing diamonds and nabbing the murderer.