1868, Morpeth. Theodora Breckenridge, still in mourning after the loss of her parents and brother at sea, is more interested in working quietly on her art at the family's country estate than she is in finding a husband in Sydney society, even if her elder sister Florence has other ideas. Theodora seeks to emulate prestigious nature illustrators, the Scott sisters, who lived nearby. She cannot believe her luck when she discovers a butterfly never before seen in Australia. With the help of her maid Clarrie and her beautiful drawings, Theodora is poised to make a scientific discovery that will put her name on the map. Then Clarrie's newborn son goes missing and everything changes.

1922, Sydney. When would-be journalist Verity Binks is sent an anonymous parcel containing a spectacular butterfly costume along with an invitation to the Sydney Artists Masquerade Ball the same day she loses her job at The Arrow, she is both baffled and determined to attend. Her late grandfather, Sid, an esteemed newspaperman, would expect no less of her. At the ball, she lands a juicy commission to write the history of the Treadwell Foundation, an institution that supports disgraced young women and their babies. As she begins to dig, her research quickly leads her to an increasingly dark and complex mystery--a mystery fifty years in the making. Can she solve it? And will anyone believe her if she does?