When Special Agent Will Trent arrives in Grant County, he finds a police department determined to protect its own. Officer Lena Adams is hiding secrets from him, and while her role in the death of the county s popular police chief is unclear, that man s widow, Dr. Sara Linton, desperately needs Trent s help to crack the case of a prisoner s death. While the police force investigates the murder of a young woman pulled from a frigid lake, Trent investigates the police force. Caught between two complicated and determined women, trying to understand the facts surrounding Chief Tolliver s death, Trent will uncover explosive secrets and confront a thin blue line that could be murderous if crossed."