Late 1930s. When World War II was declared, Mavis Batey, previously studying German Romanticism, abandoned her studies to do her duty for her country. At Bletchley Park, Britain's best kept secret, she became one of the first women codebreakers, a pioneer and a star, breaking codes vital to bringing peace.

Mavis Batey, a unique biography, delves into the life of one of Britain's best female codebreakers, taking the reader through the war and to the arrival of peace, when Mavis turned her attention from breaking codes to the conservation and preservation of gardens. Mavis became an important figure in conservation, becoming President of the Garden History Society, which, under her watch, became an academic society and campaigning force for the protection of landscapes, parks, and gardens of historic interest. She also lobbied Parliament, fighting threats of encroachment and misuse of land. Acts of Parliament were passed, English Heritage was established, and grants were introduced. Historic gardens became officially recognised as essential components of European culture and her National Register of Historic Gardens came to fruition. Mavis's passion was writing and she wrote many books.

Mavis was finally awarded the RHS Veitch Memorial Medal and the MBE for Services to the preservation and conservation of historic landscapes. Mavis never did retire: her final project was to inspire an American Garden Trail for Bletchley Park which she signed off just a few months before her death in November 2013.