Approximately month fourteen. Ben is now a member of the family group, but David is concerned that he and Joanna are becoming very close. He tries various means to keep them apart, despite Elizabeth's view that the more he tries , the more the young couple will seek to see each other. Billy and Christina are trying to secretly build a raft to explore a nearby river, but David's insistence on them doing school lessons is hampering their progress. Billy tricks Emily into doing the schoolwork for them and the raft progresses. When Billy overhears Ben declaring his love to Joanna, he foolishly tells Christina, who lets it slip at the family dinner table. David is outraged and a confrontation occurs between the father and the young lovestruck youth. Banished from the compound, Ben goes to live in a cave. Billy and Christina's raft voyage is cut short when it falls apart. Having gained dry land the youngsters are confronted by a large wild dog. Ben rescues them and takes them safely home. ...