During childhood our bodies are building up the mechanisms that allow us to survive, at the same time as facing some of life most deadly enemies. We find out why children are particularly vulnerable to some hazards, whilst also having incredible powers of survival. And how modern medicine works with the growing body to overcome the hazards of childhood. This episode follows three children: one undergoing a heart transplant, another having an asthma attack and a third with injuries caused by falling under a train.