The great Metropolitan Observatory is the pride of 22nd century engineering and science. When the astronomer Dr. Henry Brunner is found there, battered and strangled to death, there are four suspects present with reason to hate him: his immediate assistants, and the janitor who owns a fantastic Martian spider pet…And what is the connection between the star Betelgeuse, which Brunner had been studying, and the astronomer’s murder? Scientific detective Adam Quirke is called in to investigate the seemingly insoluble mystery!