In chapter sixteen, the reader learns the significance or meaning of the title of the novel, Cue for treason. Wrote out the speech which this cue can be found.

The signal for the attack on Queen Elizabeth, plotted by the men was to occur during the course of the play, Henry the Fifth. In other words, the shot (or cue) will occur at the same moment the stage cannon goes off. Thus, the shot is a cue for the men to enact their treason.

"Oh, most actors will do anything if it's made worth their while. Of course, he's scared for his skin afterward, but we persuaded him. He'll fire his shot just at the moment when there's a terrific row of stage cannon. If people hear the shot, they'll think it's part of the
play."