Beth Rich, author of fiction books It Could Have Been Murder centres on three friends who start Diamond Teams, a murder adventure company that assists teams or individuals in planning every step of a murder, including choosing a target, every detail, and every contingencyall without actually killing anyoneand then conducting a thorough debriefing with the client. To make sure Diamond Teams doesn't help someone kill a target, each client must pass a rigorous screening procedure. However, one client eludes them after 20 years. After his project was cancelled, he now seeks retribution. The ex-client has a different approach than everyone had anticipated, therefore Diamond Teams needs to devise a plan to deal with him. Before the former customer causes them irreparable harm, Diamond Teams must outsmart and outperform him.