It’s Christmas, and Phryne has an invitation to the Last Best Party of 1928 hosted at Werribee Manor House and grounds by the Golden Twins, Isabella and Gerald Templar. Phryne is of two minds about going. But when threats begin arriving in the mail, she promptly decides to accept the invitation. At the party she dallies with two polo-playing women, a Goat lady (and goat), a large number of glamourous young men, and an extremely rude child called Tarquin. The acolytes of the golden twins are smoking hashish and dreaming. It all seems like good, clean fun until three people are kidnapped, one of them the abominable child. Phryne must puzzle her way through cryptic clues to retrieve the hostages and save the party from further disaster.