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, Greg and Jenny are still searching for Peter. Greg and Jenny are becoming closer. They meet a man called Charles Vaughan (Denis Lill), a self-sufficiency expert, who has sobering theories about the number of survivors of 'the death' and their prospects for the future. He invites them to join his community, but it soon becomes clear that he has a hidden agenda which could involve Abby...

A young woman called Wendy (Julie Neubert) and an old woman called Emma (Hana Maria Pravda) have foraged since 'the death' but are now going hungry. Wendy meets Tom Price (Talfryn Thomas) and steals his food. Abby meanwhile rescues Emma from a pack of wild dogs, whilst Greg, Jenny and the children draw them off in their minibus. Tom wants his revenge on Wendy but doesn't reckon on Abby's presence. Meanwhile Greg and the others arrive at a deserted country grange, which may be just the place they need...

Petty arguments are dividing the ever growing community at the grange. Abby decides on a party on May Day as a remedy. The pary goes well and spirits are raised. However, the next morning they awake to discover that one of their number has been brutally murdered. The community meet to decide how to deal with the person they believe to be the murderer...

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...

When there are complications after the birth of Jenny's baby, Ruth knows that the only course of action is to locate some medicine to treate her. Paul, who is now in love with Ruth, elects to go on the dangerous journey into Birmingham to find what Ruth needs. Eventually Paul returns, but he reveals that he doesn't fell too well. Ruth isolates Paul in a barn to prevent the possible spread of infection and begins to treat Jenny whose condition has worsened...

Greg and Charles arrive at the London settlement and are reunited with Ruth. She tells them she can't leave the sick there and come back to Whitecross, especially as her assistance will be needed if the community is to be re-located to the Isle of Wight as planned. When Ruth learns from Nessie that Manny has no intention of taking the community out of London, she agrees to an escape attempt with Greg and Charles...

When a former vicar, Lewis Fearns (Roy Herrick), arrives at Whitecross and reveals his occupation, community life is disrupted. Charles becomes worried that the distractions caused by Lewis may be very damaging given the hard work that is required to sustain the settlement. Is there a place for God and a return to religion in the new order of things..?

Ruth invites members of a failed community to join the Whitecross settlement, despite the fact that they have been exposed to a disease. When Arthur and Jack contract the illness she fears she may have made an error in judgement. Meanwhile, the self appointed leader of the young new arrivals, Mark Carter (Ian Hastings), advises Charles on where he is going wrong agriculturally and draws up a new plan for him to examine...