The Purity Plot

Overview: The Family D'Alembert series is a set of science fiction novels by Stephen Goldin, the first of which was expanded from a novella by E. E. "Doc" Smith. Jules and Yvette D'Alembert are a brother and sister team of aerialists in the D'Alembert family Circus of the Empire and also work as agents in SOTE, "The Service of The Empire", the imperial intelligence agency.