Our book is Frog Music by Emma Donoghue.
San Francisco, 1876: a stifling heat wave and smallpox epidemic have engulfed the City. Deep in the streets of Chinatown live three former stars of the Parisian circus: Blanche, now an exotic dancer at the House of Mirrors, her lover Arthur and his companion Ernest. When an eccentric outsider joins their little circle, secrets unravel, changing everything - and leaving one of them dead. Inspired by true events, Frog Music, by Emma Donoghue, author of the award-winning Room, is an evocative novel of intrigue and murder: elegant, erotic and witty. https://www.amazon.co.uk/Frog-Music-Emma-Donoghue/dp/1447249747