Sir Baldwin is preparing for his marriage when he learns that a guest, Sir Roger, Squire of Throwleigh, has died. Herbert, only five years old, is heir. But his mother unfairly blames him for her husband's death. Baldwin is concerned about the boy's lack of protection.

When Herbert is killed by a horse and cart in an apparent accident only days later, Baldwin and Simon suspect foul play. They travel to Throwleigh to investigate, and discover a shocking sequence of events and terrible motives.