The episode delves into the fascinating history of Stockwell station on the Victoria line, which was once the final stop for the City and South London Railway—the world's first deep-level electric tube railway and a key milestone in the development of the underground. Tim uncovers remnants of a deep-level shelter utilized by Londoners during World War II. On the platforms, he highlights modern tiles featuring a swan, a nod to a nearby pub. Meanwhile, Siddy ventures into the depths of the station, discovering metallic wall tiles and cast iron pieces in an abandoned lift shaft, each reflecting a significant past. Siddy then heads to the DLR's main depot, where she learns about innovative technology designed to detect passengers on the tracks and gets a sneak peek at their new train fleet undergoing test runs. At the Museum depot, Tim examines artifacts from the DLR's history, including models of the original trains from 1986.