At the House of the Magician by Mary Hooper (author)

Intimidated by her drunken father, Lucy runs away from home in fear for her safety. She is taken on as a maid at the house of Dr Dee, court magician to Queen Elizabeth I, who relies upon him heavily – even down to advising the date of her coronation. The household is a strange and sinister place, and curious Lucy can’t help noticing things that disquiet her. But when she stumbles across a plot to assassinate the queen, Lucy must find a way to warn her…