The Tunnel: Mongolia: Primal Force, Book 3 (Unabridged‪)‬

Hell comes to Earth....

Hell is unleashed when an American drilling company punches into a massive unknown cavern in the badlands of Mongolia. The cave system lets loose a swarm of creatures unknown to science and hungry for flesh. With the body count climbing every night, Jarrett Taylor and his Primal Force are brought into eliminate the terror—one way or another.