When a bomb explodes at the Washington Monument, the Capitol K-9 Unit goes on high alert. Though injured in the blast, K-9 cop Isaac Black is determined to get to the bottom of the situation. He'll follow every lead, including investigating his ER nurse's suspicious behavior. He soon learns Daniella Dunne has long been in a witness protection program. And it's apparent that her identity has been compromised. The killer she once sent to prison--her own father--has been released and vows revenge. As Isaac and his stalwart beagle safeguard Daniella at his family's farm, a murderer with a personal score to settle lurks in the shadows.