It starts with some great characters: Ashley, an American anthropologist with her son Jason; Ben, the Australian cave diver; Linda, an American biologist; Khalid, a Egyptian geologist; and Michaelson, the Army man with a hand full of SEALS backing him up. These people form a team that Doctor Blakely has put together to search a cave under the Antarctic continent. There are other characters that come and go, some a little more unexpectedly than others.
In the main cavern, Alpha Base, dwellings have been carved all along one wall. Thousands of years old, maybe millions, these small homes belong to an extinct humanoid creature, or so the scientists believe. There are worm holes leading off the main cavern and the team has been put together to search the worm holes. They discover right before their departure that they are not the first to go down — a team went before them but never returned. They are not only on a discovery mission but also a rescue mission.