In May 2014, fire tore through the west wing of the Glasgow School of Art, destroying its famous library. Designed by Charles Rennie Mackintosh, the building was one of the finest examples of modern architecture in the world. What followed was the biggest conservation project in Europe: to restore the building to Mackintosh's original vision. It was on the verge of completion when a second, more devastating fire struck in June 2018. Featuring behind the scenes access following the restoration process, this documentary charts five extraordinary years which saw the Glasgow School of Art make headlines around the world. A tale of passion, dedication and emotion: as the building is brought back to life only to be destroyed once more, we hear from the highly skilled conservation workers, architects, former students, local residents and artists in a compelling portrait of the battle to save The Mack.