Public defender Ashley Montgomery is shocked when a well-known local is found in a lake at the outskirts of Brine County, dead and locked inside a large toolbox. Ashley has represented the victim and her boyfriend, Noah, for many years. The Brine County sheriff's department goes after Noah as their main suspect, but Ashley is intent on his innocence, and she injects herself into the investigation to protect him. A search of his house turns up a series of letters addressed to Erica. The letters prove that someone else was in contact with the victim before her death, but a deputy sheriff confiscates them before Ashley can get a closer look. The stakes rise even higher when other women in town begin receiving similar letters, including Rachel, Ashley's close friend and long-term house guest. Now, Ashley must race against the clock to discover the identity of the killer...before he adds another victim to his list.