Lalmohan Ghosh, 1849–1909, President of the Indian National Congress
This apparently simple problem takes Feluda, Topshe and Lalmohan babu to Shimla and into a realm of deceit and mystery (Bengali: rahashya) involving a long-forgotten diamond and an old priceless manuscript titled A Bengalee in Lamaland, written by Shambhu Charan Bose.