Sinclair investigates the disappearance of a diamond necklace from the room in which an apparently rich man died in. The man's mistress, his personal manservant, his wife and a cool young criminal all play their part in his ultimate recovery of the diamonds for the jewellers - but he too has to split his reward. The businessman not only indulged in extra-marital liaisons but was bankrupt and preparing to flee the country ... (PB)