Déja vu: as Guy Birkett goes through the day he has a nagging feeling that he's been here before, experienced this already; except the details are always different. Is it conceivable that he is merely a simulacrum, the ultimate in consumer market surveying?

An American insurance investigator is sent to Rhodesia to investigate the mysterious death of a diamond broker who drowned whilst diving off the coast. The broker was insured for $1 million so the insurers are suspicious.