30 April 1924. At the Court of the King's Bench in London, the highest court in the Empire, an English judge and jury heard the case that would change the course of India's history: Sir Michael O'Dwyer, the former Lieutenant Governor of the Punjab - and architect of the infamous Jallianwala Bagh massacre - had filed a defamation case against Sir Chettur Sankaran Nair for having published a book in which he referred to the atrocities committed by the Raj in Punjab.