Blood Ties — Warren Adler

During a family reunion at their ancestral castle, the famed Von Kassel family -- arms dealers for over a hundred years -- suddenly find themselves in possession of stolen plutonium capable of creating the most destructive weapon on earth. Previously aloof from the moral implications of their business, the family is torn apart by the deadly potential of their recent acquisition. Family conflicts are ignited that had long been avoided in order to maintain solidarity and the insulation of wealth and power. Through fascinating and startling familial relationships, the reader is drawn into the web of power and intrigue that motivates people who once believed they were above moral or ethical considerations.