One year after the apocalypse, an astronaut falls from space.'Major Tom' Corbett has come home - but it is a very different world than he left behind.His life-pod has touched-down into the middle of a nautical war, as massive mega-tooth sharks clash with gigantic reptilian sea-monsters - a conflict that spreads as giant prehistoric alpha-predators struggle for ultimate dominance on both land and sea.And could their battle hide a deadly secret buried deep beneath the ocean - the final Harbinger of human-extinction?