Violence, greed and betrayal threaten the remote communities of East Anglia in the seventeenth century, when ruthless and unscrupulous speculators steal their common lands, while fanatic Puritans bring accusations of heresy and witchcraft. Granddaughter of a local hero, Mercy Bennington moves out of the shadow of her elder brother to become a leader of the protestors, finding the strength to confront the enemies who endanger the survival of her village and her own life. Yet the violence wreaked upon the fragile fenlands unleashes a force no one can control - flood.

In 1648, the coldest year in living memory, Mercy Bennington and her neighbours struggle to rebuild their lives after the disastrous man-made flood, but the mysterious speculators are still bent on seizing their lands. The local magnate promises to help, but does nothing. Mercy's brother Tom, crippled in the earlier attacks on the Fens, returns to Gray's Inn in London, but his legal studies are not his only goal. Somewhere in London there must exist a copy of the ancient charter granting ownership of the common land to the fenlanders, provided that Tom can find it before his enemies have the...