A virulent flu bug is spreading through the country like wildfire. Abby Grant (Carolyn Seymour) and her husband David (Peter Bowles) are aware that the flu has reportedly claimed millions of people's lives in China, but they don't think that could happen in England. Abby becomes ill and takes to her bed. Meanwhile Jenny Richards (Lucy Fleming) learns from a doctor that this is no flu bug and that hundreds are now dying. Acting on his advice she flees London for the countryside. Abby wakes days later and fears that she may be the only one left alive...

Abby meets Arthur Wormley who has some strong ideas about how the survivors of 'the death' should organise themselves. Meanwhile Greg Preston (Ian McCulloch) meets a strong willed woman called Anne (Myra Frances) who needs his help to rescue a man who is trapped under a tractor in a nearby quarry. Elsewhere Jenny is still wandering the countryside alone...

Abby, Jenny and Greg have made an abandoned church their base. Abby hopes to find her son Peter. They make a trip to a nearby supermarket to gather some food supplies and encounter some of Wormley's men who insist they leave their loot. Jenny and Greg overpower them and they escape. The men are intent on revenge and begin to search the countryside for the trio...

Abby becomes separated from Jenny and Greg and rescues a man called Jimmy Garland (Richard Heffer) who is waging his own personal war against a man called Knox (Peter Jeffrey). Garland is heir to the Waterhouse estate that Knox has taken over and he wants it back so he can lead the community that has started there. Abby is captured by Knox and he tries to convince her that Garland has aggravated the situation and that he is willing to co-operate...

A pregnant young woman called Laura arrives at the grange, seeking shelter from her partner, a man called Huxley, who wants her back but doesn't want her unborn child. Abby and Greg argue as to whether she should be allowed to stay. When John and Lizzie unknowingly give away the fact that Laura is staying at the grange, Huxley embarks on a series of reprisals until the community agrees to give up Laura to him....

When a flood destroys both their crops and stores, the survivors decide to trade the petrol in the tanker driven there by Donnie and Anne, as its the only thing of value they have left. Greg and Jenny set off in the tanker to trade with a nearby settlement. However they are followed by a man called Lawson and his two cronies, who want the petrol for themselves at any cost...

Abby is tiring of life at the grange and her thoughts turn to resuming her search for her son. After a row with Greg over the taking in of a sick girl, Ruth. Abby sets off for Waterhouse to find Jimmy Garland. Meanwhile Greg and Arthur make their first attempts towards federating the communities that have sprung up since 'the death'. When Ruth recovers, Greg and Jenny discover she is a former medical student and that she has some startling news for them...