- Peter Brownrigg – Narrator and protagonist. 14-year-old Cumberland boy, Kit's friend. Peter is a very adventurous boy who can't stay out of trouble. Wanted by Sir Philip Morton
- Kit Kirkstone[b] – Protagonist. 13-year-old runaway girl, real name Katharine Russell, Peter's friend
- Sir Philip Morton – Antagonist. Ruthless landlord and conspiracy leader
- The Yellow Gentleman (Sir David Vicars) – Playhouse pirate and part of the plot to kill the Queen.
- Mr Desmond – Actor
- Mrs Desmond – Mr Desmond's wife
- Anthony Duncan – Conspirator
- John Somers – Actor, conspirator, assassin
- Tom Boyd – Secret agent
- Sir Joseph Williams - Counselor of Queen Elizabeth
Historical characters
- Mr Burbage – Actor and owner of the Globe Theatre in London
- William Shakespeare – Playwright and actor
- Sir Robert Cecil – Government minister and head of the Queen's Secret Service
- Sir Francis Bacon – Philosopher, statesman and essayist; cousin of Sir Robert Cecil
- Queen Elizabeth I of England- Ruler of England and targeted to be killed by the conspirators
