First published 1942, 1951 reprint. pp.191 (no dustjacket, name on fep) b&w illusts #270824

(from biggles.info)

Biggles, Algy and Ginger are flying an amphibian called the Wanderer to Central America to examine the possibilities of an air service between British possessions on the mainland and the West Indies. Stopping at Belize, Biggles looks up an old friend called Carruthers who is acting Governor there. Carruthers tells Biggles of a problem he is having with the so called ‘King of the Forest’, who is interfering with supplies of chicle (the sap of a tree used as a basis for making chewing gum) – the colony’s most important export. Biggles offers to use his aircraft to help out, as Belize has no air force. Starting by exploring the so called ‘unknown river’, Biggles comes across a wounded native chicle collector, they nickname ‘Dusky’. Dusky had been shot whilst escaping virtual slavery by a man called Cristoval Bogat. Dusky has a story to tell. Bogat is the right-hand man for the ‘King of the Forest’. Carruthers and his assistant Marcel Chorro visit Biggles. Carruthers swears in our three heroes as special constables in order to enable them to deal with the ‘King of the Forest’. After flying Carruthers and Chorro back, Biggles finds his aircraft has been sabotaged. Bogat and his associates attack Biggles’ camp and our heroes are forced to fly off. Ginger spots an old ruined city on a plateau in the mountains and Biggles lands in order to explore. They discover a huge staircase carved in the side of the mountain that leads down to the jungle. Dusky thinks this may lead to where he was held captive as he recalls seeing steps carved into a mountainside. Biggles and Ginger go down to explore and accidentally meet the ‘King of the Forest’ in his own base. Captured, they are put into a cage divided into two, with a Panther in the other half. The plan is to feed them to the panther. Algy, who had been left with the aircraft, sets off on the long trek down the mountain steps and is able to rescue Biggles and Ginger. Pursued up the steps, our heroes get away in their aircraft but not before a bullet has holed their fuel tank and forced them to land on the river. Here they face a number of perils before they are able to obtain more fuel sent to them by Carruthers. A storm-swollen river forces Biggles to take off without Algy, Ginger and Dusky. Biggles flies back to Carruthers to report on progress so far. Whilst he is away, Algy and Ginger are captured by natives and meet up with another captive, an American called Eddie Rockwell. Eddie has come to Belize on a treasure hunt but his business partners had betrayed him and left him to die in the forest. Bogat attacks the native village and captures the three white men and takes them to the ‘King of the Forest’. Biggles returns and Dusky is able to tell him what has happened. Following on, Biggles finds himself returning to the mountain plateau via the lengthy flight of steps. Algy, Ginger and Eddie are being used, amongst others, as slave labour to dig for the treasure. The two men who abandoned Eddie have now joined forces with the ‘King of the Forest’. Biggles, disguised as a native, joins Algy and Ginger and later helps them shoot their way out. Ginger however, has discovered a secret chamber whilst digging. After the initial escape, our heroes hide in an abandoned house on the plateau but later under the cover of darkness, they move to hide in Ginger’s hidden chamber. Biggles goes to scout around and whilst he is away, the house where they were hiding is blown up. Unbeknown to Biggles, this has the result of trapping Algy, Ginger and Eddie. Biggles returns to find Dusky who he had previously left when he joined the slave labour party. Returning down the steps, Biggles captures Bogat and Chorro who has been betraying our heroes. During an attack by native Indians, both Bogat and Chorro are killed. Returning to the aircraft, Biggles and Dusky fly back to Carruthers and return with a small army in order to take the King’s base. Meanwhile, Algy, Ginger and Eddie have found a secret passage that has lead them to the treasure. Further exploration helps them find a way out. Meeting up with Biggles and his reinforcements, the King of the Forest is captured and taken back to civilisation to be tried.