Teenage twins Kit and Christy have grown up amid grinding poverty in their Essex village. As Christy has been “simple” from birth, Kit is literally his brother’s keeper. But the latest hardships visited upon their country home by the Great Frost of 1683–84 bring Kit to frustration and despair, and he abandons Christy to make his way to London, seeking to better himself.
There he finds work as an apprentice to a struggling artist and much else to take his mind off what he has left behind. But the time comes when he can no longer ignore the problem of his brother.