This is a novel imbued with the scents and tastes of its setting – an alternate Renaissance Italy, where the precociously Machiavellian Caterina de'Medici (aged eleven) is threading her way through a maze of political and magical intrigues.
The viewpoint character is not Caterina herself, but Tommasso Arista, her cook. Tommasso isn't a mere kitchen boy, but an artist in his own right: apprenticed to Cellini, he is Michelangelo's lover and Caterina's confidante. His family tree includes not only prestigious cooks, but his grandmother Angelina – whose amazing recovery from a debilitating illness is popularly ascribed to her occult powers – and his dead sister Ginevra, whose spirit apparently lives on in a ruby pendant around Caterina's slender neck.
Tommasso's everyday life is drawn as a fascinating and frustrating melange of famous names, kitchen feuds, mouthwatering recipes and occult visions. His recipes are described in tantalising detail (this is most definitely not a book to read while you're dieting) and, while some of the epicurean details may seem anachronistic – were turkey and coffee well-known New World imports as early as 1530? – Roessner's research is sound enough in other areas to give verisimilitude to the more obscure details.
Tommasso understands only a little of the cosmic events unfolding around him - and so, perforce, the reader is similarly confused. It seems that Caterina is just one incarnation of a being who inhabits many planes, and who has chosen to be born into the nobility of 16th-century Florence in order to combat the forces of darkness. Caterina regains awareness of her greater self only in dreams, and during her waking hours has no knowledge of the choice she's made.
There's plenty to distract her, though. Her magical powers are gaining strength as she nears adolescence, and she is uneasily aware that a battle between good and evil is being fought through the streets of Florence and Rome. Caterina herself, Tommasso and her beloved cousin Ippolito are game pieces on the side (of course) of Good. Ranged against them are the villains of the piece – Alessandro de'Medici, ostensibly her half-brother but probably the Pope's bastard son; Lorenzaccio de'Medici, another cousin: and an array of necromancers, demons, assassins and politicians. Their aim is not clear, but indications are that it is Evil.
Those who haven't read the first in the series, The Stars Dispose, may find the plot convoluted and obscure. There is no summary of the events recounted in the previous novel: this, perhaps, is why the forces of evil seem no more than mildly unpleasant.