Jim Al-Khalili traces the discovery, just under two hundred years ago, that electricity and magnetism are linked, and follows the scientists and engineers who turned that finding into a working power system. This episode of the series centers on the maverick inventors who figured out how to generate electricity in something close to limitless quantity once the magnetism connection was understood, then had to work out what to do with it: drive machines, send messages across continents, and light homes that had never known anything but candlelight or gas. Al-Khalili moves through the period's competing claims and rushed patents, showing how a discovery made in a lab became infrastructure within a single century. The episode treats the science plainly, walking through demonstrations of the same principles the original researchers used, so the leap from curiosity to power station is visible rather than assumed.