Tatters of the King (2006)

A 1920s campaign for Call of Cthulhu, beginning in Britain, then incorporating travel to Italy and India.

From the back cover:
"The stars are right. Hastur's gaze gains brief focus upon the Earth, and things change.

Tatters of the King is a Call of Cthulhu campaign suitable for four to six investigators: ideally one should be a psycho-analyst or alienist and published in this field, and one or more of the others should be involved in the creative arts. It is convenient if the investigators live in or near London, but one or all can be foreign-based if they are prepared to travel to Britain to address events. Detailed advice on options for involving the player characters is provided."