Can a K-9 team stop an assailant with a deadly plan?

When someone shoots at volcanologist Aubrey Smith on Mount St. Helens, it's up to K-9 officer Isaac McDane to protect her even though she broke his heart a decade ago. But as people keep dying and signs point to Aubrey's sister being involved or the next potential victim, they'll have to work together to track down the killer before he finishes his hit list.