[1][2] It was first published in the UK on 6 April 2017 by Hodder & Stoughton (ISBN 978-1-473-61343-0) and in the United States in 2017 by St. Martin's Press.

[3][4] The tale is set in Ancient Rome and opens in September AD 89, immediately after the previous novel The Graveyard of the Hesperides closes (Flavia's husband having been struck by lightning during their wedding celebration).

The plot also involves a vicious white cat, a war elephant, a military archive, cataphracts and several references to public toilets including "the event which would supersede everything else when the Daily Gazette wrote up today's events".

[6] The UK paperback cover image is of a two-faced Janus head from Vulci.

[7] Writing for the Historical Novel Society, Marilyn Sherlock positively compared it to Davis' Marcus Didius Falco series and called the characters "well-drawn".