Why does Cue for Treason by Geoffrey Trease have that title?

Answer 1

because, in the story it is based on the theatre, there fore " cue " and treason meaning a violation of trust and or betrayal, so if you read the book you will see that, there is a lot of treason . so hence the title cue for treason meaning a cue for betrayal

The story is set in Elizabethan England when the ultimate treason would be an attack upon the Queen herself. The two young heroes of the story, Peter Brownrigg and Kit Kirkstone (Katharine Russell disguised as a boy) uncover a plot to assassinate Elizabeth - that is the Treason. A sub-plot involves Peter, and later Kit, escaping from the vengeance of Sir Philip Morton over Morton's ruthless plans to dispossess Peter's family, and others, of their farms. They escape by joining a troupe of travelling players, and through that employment they make their way to London and meet Shakespeare and Richard Burbage, so eventually warning the Queen of her danger. And there you have the Cue of the title.