Miss Bianca is a white mouse of great beauty and supreme self-confidence, who, courtesy of her excellent young friend, the ambassador's son, resides luxuriously in a porcelain pagoda painted with violets, primroses, and lilies of the valley. Miss Bianca would seem to be a pampered creature, and not, you would suppose, the mouse to dispatch on an especially challenging and extraordinarily perilous mission. However, it is precisely Miss Bianca that the Prisoners' Aid Society picks for the job of rescuing a Norwegian poet imprisoned in the legendarily dreadful Black Castle. Miss Bianca, after all, is a poet too, and in any case she is due to travel any day now to Norway. There Miss Bianca will be able to enlist one Nils, known to be the bravest mouse in the land, in a desperate and daring endeavor that will take them, along with their trusty companion Bernard, across turbulent seas and over the paws and under the maws of cats into one of the darkest places known to man or mouse. It will take everything they've got and a good deal more to escape with their own lives, not to mention the poet.

Margery Sharp's classic tale of pluck, luck, and derring-do is amply and beautifully illustrated by the great Garth Williams.