There is a much excitement when a balloon passes over Whitecross. However, when the balloon comes down and its occupant is found dead a mystery is left behind. The man is discovered to be a Norwegian and he has in his possession various items that suggests he has been mapping the nation's settlements. When Melanie and Alan meet one of the ballonist's acquaintances, Seth, they learn that the man had been travelling with his daughter Agnes. When Agnes eventually arrives at Whitecross things will never be the same again for our survivors...

When Sally becomes pregnant by Alan, Charles is overjoyed, thinking this will encourage a baby boom at Whitecross. Sally wants to live with Alan as his wife but he has other ideas. As the situation becomes more tense, Charles crosses swords with Melanie, Ruth and even Pet...

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...

Mina befriends a man called John Millen and arranges to meet him at Whitecross at a later date. When John fails to arrive and two other men come to the settlement on his barge (one of them wearing John's hat) Mina fears the worst. Charles and Greg welcome the men, Kane and Grice, but also have misgivings about their intentions. Pet is suspicious too, as she recognises Kane from before 'the death'...

Charles and Pet are returning from a salt collecting expedition when they meet two other travellers who become very ill. They take them to a nearby settlement in an old army camp. The community there is run like a police state where eugenics, euthansia and religious fervour all hold sway. The people there are led by a charismatic man called Max Kershaw and his second in command Joy Dunn. Pet is fearful that they may not be allowed to leave, whilst Charles is summoned to speak to the community's council...

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..?

Charles and Greg hold a meeting at Whitecross with leaders of nearby settlements to try to come to some co-operative agreements. The event is interrupted by the news that the wife of one of the leaders has been killed by a sniper. It is soon learned that the sniper targets young women and seems to be travelling towards Whitecross. Jenny, bravely volunteers to act as bait to bring the sniper out into the open...

When Mina (Delia Paton), an eccentric member of the community at Whitecross, spurns Hubert's unwelcome attentions, he begins to spread vicious rumours that she is a witch. When John and Lizzie see Mina bake a clay figure representing Hubert and Pet and Peggy add up other recent events, they begin to believe that Hubert may be right......

A man called Alistair arrives at Whitecross and considers the possibility of staying there permanently. He hides the fact that he is a convicted child killer because he feels that he is a different person now and has paid the price for his crime. Unfortunately Hubert finds a newspaper clipping belonging to Alistair which details his past. He passes the information on to others. When John goes missing, Alistair is immediately suspected...

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...

A couple called Penny and Amul arrive at Whitecross claiming to have news of Abby. Ruth goes with them thinking her medical skills are needed at the place where Abby is staying. She soon learns that she is being taken to London instead to help nurse the sick there and that Abby has already moved on. The large settlement in London is run by a man called Manny who does not want Ruth to leave. When Greg and Charles fear for Ruth's safety they journey to London to rescue her...

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 travels to a community at Whitecross to trade with its leader Charles Vaughan (Denis Lill) who he last met at Mardell. Jenny is now pregnant so Greg also seeks news of Ruth's whereabouts, as she promised to return to help with the birth. Whilst Greg is away, a fire destroys the grange. The survivors of the blaze are soon reunited with Greg, who leads the way back to Whitecross where they hope to stay, at least until Jenny has had her baby...