Fresh out of Cambridge University, the young Mycroft Holmes is already making a name​ ​for himself in government, working for the Secretary of State for War. Yet this most British of civil servants has strong ties to the faraway island of Trinidad, the birthplace of his best friend, Cyrus Douglas, a man of African descent, and where his fiancée Georgiana Sutton was raised.

Mycroft’s comfortable existence is overturned when Douglas receives troubling reports​ from home. There are rumors of mysterious disappearances, strange footprints in the sand, and spirits enticing children to their deaths, their bodies found drained of blood. Upon hearing the news, Georgiana abruptly departs for Trinidad. Near panic, Mycroft convinces Douglas that they should follow her, drawing the two men into a web of dark secrets that grows more treacherous with each step they take...

Written by NBA superstar Kareem Abdul- Jabbar and screenwriter Anna Waterhouse, Mycroft Holmes reveals the untold story of Sherlock’s older brother. This harrowing adventure changed his life, and set the​ stage for the man Mycroft would become: founder of the famous Diogenes Club and the hidden power behind the British government.