When everyone around him vanishes overnight, scientist Zac Hobson (Bruno Lawrence) finds himself seemingly the only person on the planet. The isolation initially drives him to the brink of suicide, but eventually Zac adapts to a day-to-day routine. After meeting two other survivors, Joanne (Alison Routledge) and Api (Peter Smith), a Maori, the trio roams New Zealand trying to understand what caused everyone else to disappear, why they remained behind -- and whether disaster will strike again.