When they receive a phone call from Peter Longfield's brother David who informs the family that his uninsured townhouse has burnt down, they are asked to look after his three children, 16-year-old Cyril, 14-year-old Melisande and 10 or 11-year old Roderick.

The Mistletoe Farm children are initially alarmed of the prospect of their three spoilt cousins from the city living with them, and at first they find it difficult to get along with each other.

But after a number of challenges and hardships affect Mistletoe Farm, the city of Longfields learn to adapt to life in the country and get along with their cousins.

In the second book, Six Cousins Again, Cyril, Melisande and Roderick have moved into a nearby, much more modern farm with their parents.

Their mother, Rose, has difficulty adapting to the life of a farmer's wife, their father, David, has various setbacks, and the children have trouble settling down.