When Sarah Jane disturbs a burglar in the night, she is surprised to find a middle-aged woman, her pockets stuffed with jewellery, demanding gold. The next day, she reads a newspaper story about a granny who broke into a jewellers, and then Maria reports that a woman has been stealing rings and necklaces from the girls' changing room at school.

All the women had recently attended the Auriga Clinic, a private health centre specialising in treating muscular aches and pains. Is there a link between the clinic and the odd behaviour of its patients?

Sarah Jane decides to find out, but she soon discovers that the clinic's secret agenda is more sinister than she could ever have imagined...