The Caves Of Steel was an early Isaac Asimov 'robot' story. On another planet the inhabitants have extreme agoraphobia and cannot tolerate living under the open sky, with its fierce sun. A human detective, Lije Bailey, and his robot assistant R Daneel Olivaw, are sent to investigate the murder of a VIP who lives in an enclave out in the desert. No weapon was found in the enclave and only a robot could have crossed the open space between the 'caves of steel' where everyone else lives and this desert mansion. But a robot is bound by Asimov's 'Three Laws Of Robotics' and so could not have been involved in the murder.... or could it?