The staff of the Sector General hospital could not be more varied. There's Thornnastor, the huge, six-legged Tralthan, whose brilliant brain has made him Chief Pathologist. Dr Prilicla, a fragile, insect-like empath who can sense a patient's mental state when everything else has failed. Naydrad, a Kelgian, who are known to be the best nurses. And then there's the senior physician, a human called Conway, who was given a chance of a new mission into space, treating emergency patients out in the stars, patients of every size, race, alien form and physiology - all waiting for the arrival of the Ambulance Ship. But now the medics are in more danger than the victims they are trying to help . . .