Early one frigid morning in January, a young man named Thos Kahale walked into the icy waters of Lake Tahoe and died a brutal death. 

Hired to investigate, Tahoe Detective Owen McKenna learns that the Hawaiian side of the man's family had a secret shrine hidden in a cave in the cliffs of Kauai. Owen flies to Kauai and hears about a long-lost manuscript that Mark Twain left when he visited Kauai in 1866. The manuscript, which would be worth millions, is rumored to have been lost in a hurricane. Owen suspects that it was hidden in the secret shrine. 

As multiple people die, Owen tracks a vicious killer who looks like a Viking. Owen follows the Viking back to Tahoe and learns of a cave of ice that is sacred to Tahoe's Washoe Indians. Thos, who was half Washoe, may have hidden the manuscript in the Tahoe cave. Only one person, whose identity is unknown, knows the answer. 

Owen and his Great Dane Spot have to find that person before the Viking does, and they are running out of time as they chase the Viking up a mountain in a blizzard to a cave of ice and a battle to the death.