From the vast island of Sumatra, Benedict Allen brings back the strangest of travellers' tales concerning black-maned ape-men as Theodore Hull - octogenarian survivor of Japanese labour camps - entices him onto the trail of the Gugu. A tangle of folktales leads Allen to the aboriginal Kubu people who can guide him into the highlands where the ape-men screech all night long, shaking every fibre of the forest. But the twentieth century is encroaching, and Kubu say that the Gugus' rage can no longer be appeased by traditional gifts of tobacco. Allen ventures into the dark, living forest, watched by unseen eyes . . .