The first book in a trilogy about terrifying genetic experiments. Danny is different. He's slower than other kids his age, and prone to violent outbursts. But when Danny runs off to find his biological mother, his older stepbrother Christie impulsively follows him. Along the way the two boys are joined by a runaway girl, a bird, and a dog that can speak to humans. However, nothing can prepare them for what they learn when they finally locate Danny's mother at her laboratory, Fourth World. It seems Danny's mother has been performing experiments - secret experiments - with terrifying genetic significance...

Christie and his friends continue their search for the missing link in the faraway Himalayas, where the answers may be found with the elusive and mysterious Yeti. Their journey leaves Danny battling his overwhelming longing for the sea, and Danny's half-sister Sandy fighting for her father's approval. The experience will bring out the best and worst in the group and eventually compel each of them to ask the ultimate What does it mean to be human?

"Origins" is written as two intertwined, parallel narratives. The first, which takes the form of a diary written by Christie at Fourth World around the year 2009, follows the fortunes of Maggie and Bernard and their assorted group of children and gifted animals. The stone which Christie has carried back from the yeti's cave (see Only Human) proves fatal. It releases an alien presence (the Yoke) which takes over the smallholding and laboratory of Fourth World and by its efforts to return to its own planet, destroys both human beings and the environment worldwide. There are few survivors but of those who do remain, two are newborn twins, Ogden and Atticus, who carry a dog and cat gene, the latest and last experiment by Maggie and Bernard in their genetic engineering research. The second narrative takes place far into the future, in a changed world where nuclear devastation and disease has reduced mankind virtually to the stone age scenario. Nessa and Farral from the warring Cat and Dog tribes are thrown together and eventually become tolerant of each other in their travels across wild mountains and nuclear waste. Terminating their journey among a small group of inhabitants in the very far north, they find that Christie's diary has survived and been preserved by this group of people. It is of course the key to the reader of this 'new world' set up. It is an extraordinary and compelling resolution to the story. Kate Thompson's final volume in the "Missing Link" trilogy is startlingly dramatic in construction and disturbingly thought provoking in content.