Though the information given by Amazon states that this is the fourth book in the 'Animals of Farthing Wood' series, it is actually the seventh (or eighth if you take the prequel, written after the other books, as the first), and last. It is also, in my opinion, the least enjoyable.
The plot follows the few remaining original Farthing Wood animals and their descendents as they fight to defend their home, White Deer Park, from an invading horde of rats - there seem to have been no rats in the Park prior to this, which is a highly unlikely starting point. I was deeply disappointed that the author, who can usually be relied upon to be fairly accurate and impartial with regards to the information he gives about wild animals, resorted in this book to every commonly-held prejudice on the subject of the rat, an animal which has already had more than its share of bad press. The fact that rats are in fact very clean and intelligent animals, and that they are as much a part of the ecosystem as any other creature, is completely ignored here - Dann hits them with every negative stereotype, portraying them as dirty, vicious, disease-ridden beasts intent on taking over White Deer Park and driving out all its other inhabitants.
The story itself, regardless of the species involved, is simply a rather uninteresting string of violence and does not hold the imagination the way the previous books did, giving the sense that the author is beginning to run out of ideas, and as a fan of the 'Farthing Wood' books since childhood, I found this a most unsatisfactory end to the series. Since either of the two preceding books could have served as the last, I feel that perhaps the author should have quit while he was ahead, rather than to milk such a successful series to the point that it ends on such a low note.