It's a tale of intrigue set at the turn of the 20th century in the seemingly genteel gardens of Victorian Britain.
Keen horticulturist sit examinations in the principles of gardening - from the names and orders of common plants, to soils, good and bad.
They compete across the country for a prestigious scholarship at the Royal Horticultural Society's flagship garden.
The news that a "Miss Harrison" is the winner rocks the establishment.
Nobody had considered that a woman might get the top mark.
"Clearly a very determined young woman, she's entered this exam, she's done well and she's claimed her rightful prize," says Fiona Davison, who looks after the libraries and archives of the RHS.
"And, she single-handedly has sent the RHS into a bit of a tail spin."
Women of all classes have long gardened as a hobby or to grow fruit and vegetables for the kitchen. But middle-class women in the 19th century were unable to become professional gardeners.
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While women such as Gertrude Jekyll were famous for creating and designing gardens, the hard labour of gardening was viewed as a man's work.
Sir Joseph Hooker, head of the Royal Botanic Gardens, Kew, wrote in 1906: "Gardening, taken up as a hobby when all the laborious work can be done by a man is delightful, but as a life's work [for a woman], it is almost an impossible thing."
Beyond the smoke
Miss Harrison was prepared to fight for the chance of entering the male-dominated horticultural profession, and bring change in society's attitudes.
Her story came to light when staff were sifting through a box of archives from 1898. They found a document marked with the initials of Reverend William Wilks, then leader of the RHS.
He had written across the top: "Only males being allowed at Chiswick, it was never contemplated that a female might claim the Scholarship."
Chiswick was then the flagship garden of the RHS, before its move, in 1904, "beyond the radius of the London smoke" to the Surrey village of Wisley.
Lawyers were consulted, and, despite Rev Wilks's attempts to win over the committee, it was decided that the word "he" in the regulations meant a woman was barred.
Ms Harrison lost her opportunity to train alongside men, and there the trail goes cold. All that is known is her surname; no letters or photographs from her have been found.
More than a century on, Fiona Davison would like to find out what happened next. "Did she carry on fighting - did she carry on into horticulture and make a living that way?' she says. "I'm really curious to know: what happened to Miss Harrison?"
She believes family members may have letters or memories of the pioneering gardener, which could solve the mystery.
By the middle of the 20th century, attitudes were beginning to shift, allowing women to train for careers. At Wisley Gardens today, much has changed since Ms Harrison's day.
The RHS is led by a woman, Sue Biggs, and women have been training in horticulture for decades.
Today's horticulture students say it's hard to imagine women being excluded from the profession.
"It makes me feel very frustrated and angry," says Naomi Trenier.
"I would hate to have been restricted in that way. And I'm grateful for the people who have gone before that make it possible. But we still need to go further to make sure everyone's included."
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