Starting in Kolkata, Sergeant traverses India from east to west, travels through turbulent Bihar state, visits the Victorian railway town of Jamalpur, and discovers why the construction of the Dufferin Bridge at Varanasi resulted in Victorian technology and ingenuity clashing with ancient religion, before ending his journey at the border with Pakistan. Even though Mahatma Gandhi denounced the railways as evil, Sergeant reveals how it became a civil engineering triumph that united the country and played a crucial role when India became independent in 1947.