After the events of The Deserter we're back on the ground and things are only getting worse. Stopmouth's old tribe are trapped, the aliens around them dwindling as the Diggers close in, while above the lights of the Roof flicker and die. Chief Wallbreaker is a coward, but a survivor, and he knows his days are numbered. The arrival of a fugitive from the roof with intelligence about the world around them and the nature of the Diggers compels him to send the tribe on a desperate and suicidal migration to where rocky hills may keep the Diggers at bay, hills occupied by another humantribe led by Wallbreaker's traitorous brother Stopmouth.

Another nasty, violent, bloody adventure of survival in a world artificially contrived to bring out the savagery in any thinking being - purely for the purposes of punishment for a generation's-gone crime and entertainment for a decadent, disintegrating society - and yet one that within the savagery allows for the flourishing of a noble selflessness amidst ignorance and casual acts of brutality, a love of family and tribe where the ultimate sacrifice is taken for granted, and never wasted.

This is the climactic volume of the Bone World Trilogy, where everything falls apart and new thinking is needed, and though Stopmouth is a figure of heroic stature, it is his selfish brother who somehow finds the vision and ingenuity and ruthlessness that may save everyone. Bone World is a world of ironies and contradictions, and this trilogy is fantastically readable and exciting and suspenseful, with wonderful characters and real emotional heft, and should easily appeal to fans of the Chaos Walking Trilogy by Patrick Ness. ( )