The dog gasped, mouthed, swung its head. It gaped and showed sharp white teeth. Then, as if it were being sick, it brought up words. The dog spoke . . .

Madi and her brother Jonjo live on the OzBase, a research center near the North Pole. Their mother is one of an international team of scientists investigating a hole in the ozone layer over the Arctic. Others, however, are involved in less honourable experiments - as the children soon discover . . .

Nicholas Fisk