The Great Exhibition, Crystal Palace, 1851: James Chance, of the glass-making firm Chance Brothers, is nervously showcasing a new lens, that, unknown to him, will revolutionise lighthouse production, propel his family business into a position of world leadership, save countless lives and have far-reaching consequences for trade, empire and the map of the world.

This is where Lighthouses begins. The true-life story that follows is of one man and his family's unexpected role in an exciting race to perfect this technology, against European rivals and colleagues, as they strive to regain for Britain the leadership position she had lost to the French in the 1820s. With support from such illustrious personages as Sir David Brewster and Michael Faraday, Chance Brothers' lenses helped light shores around the globe – from the Clipper path in the Far East to the New World emigrant route.

This fascinating story places James Chance and the Chance Brothers firm against the backdrop of a stage on which lighthouse manufacture was transformed from a craft into a scientific, high-precision industry. As a tool for globalisation, and with immense strategic and economic value, lighthouses helped to establish a network of communications that transformed the trade maps of countries and empires.