This is the 4th book in this series and I haven't read any of the others but I think I would have felt more comfortable if I had. By reading I have the impression that Hilda (and her town) are not exactly altogether human, strange things happen there, and everyone takes it all within stride. This book has Hilda joining the Sparrow Scouts, obviously to give her something to do with all her extra energy and imagination. But during this time a large hound has been roaming, and sited, in the woods beyond Trolberg. The Sparrows go camping on private Sparrow ground which has been walled off from the rest of the forest making everyone sure the girls will be perfectly safe from this supposed "creature". At the same time Hilda has come across a Nisse, a house spirit, which has been kicked out of its home. Hilda becomes friends with him, helping him to find a new home and together they manage to both find him a home and solve the mystery of the Black Hound. Cute drawings. A fun fantasy, a bit short, but it keeps you reading quickly. I wouldn't mind having read the first ones because I think if read in order, you may be fond of Hilda by this point.