In 1796, Martha becomes the mistress of the struggling Plas Ingli estate, at only 18 years old. She is pregnant and suicidal. Though she loves her husband David dearly, she is desperately lonely in a strange house and her quick wit and cutting humour make her as many enemies as friends. There are mysteries surrounding the great fire that devastated the estate but Martha's questions about it remain unanswered. Nobody else seems to realise that their haughty servant Moses Lloyd, the disinherited son of the local squire, is not as trustworthy as the rest of the family would like to think. The local gentry consider that Martha is far too clever for her own good and it seems inevitable that she will fall into a trap, designed to send her to the gallows. How can she possibly escape?