When a monster avalanche crashes down at Emerald Bay, Lake Tahoe, a young man named March Carrera is swept off the mountain highway. March's uncle, Bill Esteban, a wealthy Houston businessman with a house in Tahoe, has a hunch that March's disappearance isn't an accident. Esteban contacts Tahoe Detective Owen McKenna and asks him to investigate. Although McKenna's Great Dane Spot has some search training, McKenna decides to bring in a professional Search-And-Rescue dog that specializes in avalanches. When the dog searches the slide area, he alerts on a scent and digs up a great deal more than McKenna expected. As McKenna is pulled into a harrowing investigation, another avalanche on the other side of Tahoe claims another victim. While McKenna struggles to find a connection between the victims, the murderer reveals his presence by warning McKenna off the case. McKenna and his girlfriend, a forensic entomologist named Street Casey, are called to the morgue in Sacramento to examine an insect found in the lungs of one of the victims. Casey identifies it as a Boat-backed Ground beetle, a ferocious predatory insect that eats snails. Casey further connects the beetle to the soil of the Sierra foothills. The killer follows his warning with a bomb that almost kills McKenna's dog Spot. Despite the bomb, McKenna continues to pursue the case. He follows a lead that takes him to San Francisco's seedy Tenderloin District, where an art-collecting Chinese mobster trades in stolen detonators that can be used to set off the type of explosives that ski patrollers use for avalanche-control. McKenna connects the mobster to a dead rich girl from San Francisco's exclusive Presidio neighborhood, and then ties the girl to a foothill vineyard with the kind of soil that provides home for the predacious beetles. He believes this new information identifies the killer. Detective McKenna races back to the mountains, but arrives too late, for the suspect turns up dead, buried under another slide. When returning home, McKenna is bombed once again, this time sustaining a serious wound. Faced with losing his life or the life of his dog, McKenna contemplates quitting the case. But he presses on and learns of a striking event that happened 140 years ago, an event that all of the avalanche victims also knew about. This knowledge doesn't identify the killer, but it does indicate that there is one last person to die. McKenna realizes that the last intended victim is up on the shoulder of Tahoe's highest mountain. McKenna rushes to organize a rescue party. A violent storm is approaching, the last victim is with the killer, and there is one more avalanche coming to bury the secret forever.