How do you catch a killer when no one is willing to talk?When a homeless man is found murdered in picturesque Lincoln the police are met by a wall of silence from those who may hold the key to solving the crime. DS Catherine Bishop is drafted to infiltrate the homeless shelter where the victim occasionally spent the night but everyone seems to have something to hide. Still dealing with the emotional fallout from a previous case, Catherine struggles to adjust to the undercover job and working with a new team.

When someone close to her is injured in an attack, Catherine comes perilously close to risking her case, and her life. Is this a murder after all, or a cover for something else - with Catherine in the firing line?