1665, and the Great Plague has London in its grip. Where better, then, to hide a murdered man than among the corpses on their way to the Plague pit?When a supposed Plague victim is found with a knife in his back, John Grey, now a successful lawyer, is called in to investigate.

The dead man was known to be carrying a compromising letter from the Duke of York to the French ambassador. Now the letter has vanished and Secretary of State Lord Arlington wants it. But Arlington is not the only one trying to recover the letter.

Somebody has killed once trying to obtain it - and is prepared to kill again. Grey must set off on a journey through Plague-ravaged England to fulfil his commission and keep himself safe from his enemies - if the Plague doesn't get him first...