Lestrade arrives at Baker Street with a parcel which has recently arrived at Scotland Yard. Having examined the strange contents Holmes announces that Lestrade’s package contains nothing less than the shrunken head of Crosby, a missing banker.
Recently returned from a trip to America and the West Indies, Crosby has not been seen for six weeks. His yacht the Gyrfalcon has also vanished. It was last seen sailing out of Itchen skippered by a mysterious yacht-hand called Teddy the American.
When Holmes discovers a curious word chart in Teddy’s lodgings the mystery begins to unfold and he and Watson find themselves following a dangerous trail of curses and revenge that reaches across the world to a mountain wilderness in America’s West.
In a dramatic hunt for the killer, Watson’s life is put at risk before the investigation comes to a violent conclusion in London’s East India Docks.