In the state-of-the-art research submarine Orpheus, Captain Frances Kelly leads a team of scientists deep below the Arctic ice. They are following the path of an earlier, disastrous expedition; searching the final frontiers of Earth for unknown and remarkable life forms, attempting to find the solution to the world's escalating energy crisis.

Enduring crushing pressure, boiling vent gases, freezing temperatures and total darkness, the Orpheus arrives at the Lomonosov Ridge, an enormous area of sea bed which is disputed territory, currently under the United Nations' jurisdiction. Nobody comes here. But there is something else out here: something huge and bewildering. And, as the Orpheus crew struggle for survival and attempt to unravel the mystery, they uncover secrets more terrifying than they ever could have imagined…