Grant Blackwood

"On a routine intelligence gathering mission in Tehran, Jack Ryan, Jr., has lunch with his oldest friend, Seth Gregory, an engineer overseeing a transcontinental railway project. As they part, Seth slips Jack a key, along with a perplexing message. The next day Jack is summoned to an apartment where two men claim Seth has disappeared--gone to ground with funds for a vital intelligence operation. Jack's oldest friend has turned, they insist. They leave...

Recruited by Sigma Force to extract a Russian pharmaceutical magnate, who holds the biological key to a new weapons system, from Siberia, former Army Ranger Tucker Wayne and his military working dog Kane must solve an ancient mystery before the modern world suffers a fate worse than death.