1670. Eastwold, once one of the greatest ports in England, has been fighting a losing battle with the sea ever since it was granted its charter by King John. Bit by bit the waves have eaten the soft cliffs on which it stands, until only a handful of houses remain.

But still it sends two MPs to Parliament and rich men from London are prepared to pay well for the votes of the dozen or so remaining burgesses of the town. The voters are looking forward to a profitable bye-election, only for the Admiralty's candidate, the unpopular Admiral Digges, to end up in a fishing net, every bit as drowned as his prospective constituency. Is it an accident, as the coroner has ruled, or has Digges been murdered, as the Admiralty fears? John Grey, Justice of the Peace and former spy, receives a request from the authorities to uncover the truth.

With spring edging cautiously towards the windswept east coast, Grey starts to question the remaining residents and other well-paid officials of the non-existent town. He is met with suspicion and polite obstruction from the voters - and then another suspicious death occurs. Will Grey uncover the murderer before the last of the town vanishes beneath the waves?