A major, natural catastrophe has occurred that has taken the lives of all air-breathing creatures. Throughout the world a few individuals have survived as at the time of the devastation they were unknowingly safe from harm. Those that were underwater, miners far below the ground, hospitalised patients using breathing apparatus etc. But the total number of survivors amounted to only a few thousand and of those there were only two couples left on earth who were capable of or had the opportunity to breed - but if only it was a simple as that.
The story is full of drama, tragedy, compassion and heroics even some humour as it depicts the trials and tribulations of some of the survivors. There are chance meetings, some of which are beneficial but others result in tragedy as rebel groups resort to feudal law.
There are twist and turns as the travellers negotiate obstacles but none of this mean anything, unless the two couples not only survive but more importantly, overcome their emotions to prevent the extinction of mankind.