In the year 1665 death came calling on the city of London. Death in the form of plague. People called it the Black Death, black for the colour of the tell-tale lumps that foretold its presence in a victim's body, and death for the inevitable result. The plague germs were carried by fleas which lived as parasites on rats. Although it had first appeared in Britain in 1348, the islands were never totally free of plague, but it was like an unpleasant possibility that people just learned to live with while they got on with their business. This time it was different.