One Head Too Many — Peter Tonkin

A new investigation for Elizabethan sleuth Tom Musgrave. A mob playing football on London Bridge kick the ball over the Great Stone Gateway, where the heads of executed traitors are displayed, and it is the head of a woman that falls down the other side. As Tom puzzles over who this woman is, he uncovers the bridge's hive of ruthless businessmen, spies, and even ghosts.