Shadow of the Jaguar: The Frozen Empire. The Amazon Chronicles, #2

The Jungle infected him. The Ice will unleash him. Aryan thought escaping the Amazon meant survival. He was wrong. It was only the beginning of a terrifying metamorphosis. Now living under a false identity aboard the icebreaker Polar Star, the former diplomat has infiltrated a new expedition. His target: The Syndicate. They have moved from the jungles of Peru to the most hostile environment on Earth-Antarctica-to drill for an artifact buried beneath the Ross Ice Shelf.
But as the drill breaches the ancient ice, it wakes something that should have remained asleep. Trapped in a blinding whiteout with a team of ruthless mercenaries, Aryan realizes the strange inoculation he received in the Amazon wasn't a cure-it was a biological key. As a mysterious red mist engulfs the ship and crew members begin to die, Aryan's body starts to reject the cold. His heart rate slows.
His vision sharpens in the dark. The predator within is taking over. In a frozen wasteland where no human can survive, Aryan must stop fighting the monster inside him and become it. The Jaguar has risen.