In the short story Swan Song, Blanche Amery is the daughter of Lord and Lady Rustonbury. When Tosca opera staged by her parents results in the character Scarpia really being stabbed by Tosca, with fatal results, most regarded it as an accident or a case of the female lead being carried away by the role she was playing. However Blanche had observed the interaction between Edouard Bréon (Scarpia) and Paula Nazorkoff (Tosca) before the act began. Blanche senses that the stabbing is intentional and that it is a case of Tosca come to life. The key has to do with the unknown past of Nazorkoff.
Blanche is described as a twenty-four year old slender girl with wide blue eyes.