Deep in the heart of the night, there is always murder, passion, and lies, even when we don’t see it. But FBI agent Lilah Love has seen more than most. Years ago, while at her family’s home in the Hamptons, back in the days when she loved the wrong man and trusted the wrong people, she lived a nightmare she can never forget. That horrible night, some think that she saw a little more than she should have. It was a night that changed her life forever and made her abandon the man she’s never gotten over, and a future a future in New York near her family, for a one in L.A. as an FBI profiler. But now, a series of brutal murders connect to her home, forcing her to return to the Hamptons, where her father is the mayor, her brother is the police chief, and her ex is now running an empire believed to be as corrupt as he is powerful. 

Soon, she is certain she’s dealing with an assassin, but more and more there seems to be a connection to a very secret part of her past, and to her ex, who is still a dominant force in the Hamptons, and it seems, her life. Alphabet letters begin appearing on her car, her door, in her house, along with clues that begin to paint a picture that has her questioning everything she knows of her past and threats to that long-kept secret. She calls them her “Murder Notes” and as they continue, they become darker, more threatening, and Lilah begins to worry that “M” is for murder. Lilah must find the sender, and the serial killer, who could be one and the same, before she’s the one who ends up dead.