The Pinhoe Egg is set in the world(s) of Chrestomanci, but instead of focusing on Chrestomanci -- a position rather than a person, the title given to a nine-lived enchanter with the responsibility of regulating magic usage in a series of parallel worlds including our own -- this novel deals with the magic users who hide away almost in the shadow of Chrestomanci Castle: the Pinhoes and the Farleighs, and other more shadowy families, who inhabit small country villages and try to avoid being noticed.
Marianne Pinhoe is looking forward to the summer holidays, because she'll have time to work on her story about Princess Irene. Unfortunately, her grandmother -- Gammer Pinhoe, the head of the clan -- has other ideas. Gammer has been acting oddly of late, and the rest of the family suspect she's quite mad. Marianne isn't convinced, though Gammer's escalation of the old feud between Pinhoes and Farleighs is certainly not the work of a sane woman.
Gammer sends Marianne's brother Joe to work, and spy, at Chrestomanci Castle, where he ends up befriending Chrestomanci's son Roger: all well and good as far as Cat Chant is concerned, since it keeps Roger out of his way. Cat's found a huge, ancient egg in Wood House, where Gammer used to live: found it despite a quantity of 'Don't Notice' spells surrounding it. And the thing about eggs -- however well hidden they may be -- is that they hatch.
There's a lot of mayhem, magical and mundane, in this novel: and some of the magic is pretty dark stuff. (Mr Farleigh, the gamekeeper, nails dead animals to the fence as a warning, but there's a nastier purpose too. And hang on, isn't it quite a long time since the Castle needed a gamekeeper? And what happened to Gammer Pinhoe's husband? And why do the roads that lead away from the Castle not lead anywhere?)
There are a few things that niggle about this novel. How old is Cat? He seems very mature, and considerably more confident and assured than in Charmed Life, but I think he's the same age as Roger and Julia, and they behave much more childishly. And is Irene, Jason's wife, any relation to the Princess Irene that Marianne's writing the story about? (She does seem to break the mould, being a young woman -- rather than a girl -- who's a genuinely nice person, and on the right side: others have remarked on the lack of such characters in Jones' books.)
Niggles aside, I enjoyed this very much: there's space for Marianne, Joe and Cat to discover and demonstrate their talents, and the depiction of Gammer's decline is realistically unpleasant and unsentimental. Plenty of elements from fairytale, legend and myth; and I'm fairly sure I detect a general air of homage to E. Nesbit.