Calcutta 1837. The East India Company rules India – or most of it; and its most notorious and celebrated son, Xavier Mountstuart, has gone missing. William Avery, a down-at-heel junior officer in the Company's army, is sent to find him, in the unlikely company of the enigmatic and uncouth Jeremiah Blake. What was it that so captivated Mountstuart about the Thugs, the murderous sect of Kali-worshippers who strangle innocent travellers by the roadside? Who is Jeremiah Blake and can he be trusted? And why is the whole enterprise shrouded in such secrecy?