"A Mysterious Affair" is a suspenseful crime novel that follows detectives Jameson and Rodriguez as they investigate the murder of Alexander Ashton. Their investigation leads them to discover that Jessica Martin, a business partner of Ashton, convinced Thomas Thompson to rob and kill Ashton. When Thompson refused to go through with the murder, Martin took matters into her own hands and killed Ashton. The detectives must unravel the web of lies and deceit to bring Martin and Thompson to justice.