Hailes Castle, 1511. Midnight on a doom-laden Hallowe'en and Elisabeth Hepburn, feisty daughter of the Earl of Bothwell, makes a wish - to wed her lover, the poet David Lindsay. But her uncle has other plans. To safeguard the interests of the Hepburn family she is to become a nun and succeed her aunt as Prioress of St. Mary's Abbey, Haddington.

However, plunged into the political maelstrom and religious turmoil of the early Scottish Reformation, her life there is hardly one of quiet contemplation. Strong-willed and independent, she clashes with those who question her unorthodox regime at St. Mary's, including Cardinal David Beaton and her rival, Sister Maryoth Hay.

But her greatest struggle is against her thrawn godson, John Knox. Witnessing his rejection of the Roman Catholic Church - aided by David Lindsay - she despairs that the sins of her past may have contributed to his present disenchantment.

As he purges himself from the puddle of papistry, Knox finds his voice, denouncing everything he once held dear, but will that include his godmother, Prioress Elisabeth? And by confessing her dark secrets, will Elisabeth steer Knox from the pernicious pull of Protestantism or drive him further down the fateful path he seems hell-bent on, a path that leads to burning at the stake? In a daring attempt to shed light on a wheen of unanswered questions about John Knox's early, undocumented life, this novel throws up some startling claims and controversial conjectures.