It begins by examining the shift in the language and sound of music from the melodies and harmonies of giants such as Mozart, Haydn and Brahms into the fragmented, abstract, discordant sound of the most radical composers of the new century - Schoenberg, Webern, Stravinsky and beyond. It examines how this new music was a response to the huge upheaval in the world at the start of the 20th century, with its developments in technology, science, modern art and the tumult of the First World War. Featuring performances of some of the key works of the period, performed by the London Sinfonietta, members of the Aurora Orchestra and composer and pianist Timothy Andres, the story of this episode in music history is brought to life through the contributions of the biggest names in modern classical music, among them Steve Reich, John Adams, Michael Tilson Thomas, Pierre Boulez, George Benjamin and Alex Ross, music critic of the New Yorker.