The family's name is spelled O'Brien in the publisher's summary.
Talk about it here.
In 2009, the family was away on holiday. They went to Australia for three weeks. The family bought a lot of milk from the milkman. The milkman said that it had cost him a fortune that the family had cancelled their order because of the trip.
The O'Briens' house had been displaced in time when they were gone. However, Sarah Jane Smith and her team helped to place the house into the correct time again, before the family returned from their holiday. (AUDIO: The Ghost House)