The Pinhoe Egg

Cat Chant and Marianne Pinhoe have discovered something exciting – something truly precious, very strange, and valuable. An egg.
An egg that has been hidden away in an attic for who-knows-how-many years. An egg protected by some strong “Don't Notice” spells. An egg that Marianne gives to Cat, even though he lives at nearby Chrestomanci Castle. Chrestomanci himself, the strongest enchanter in the world, is sure to be interested in the egg – and interference from the Big Man is the last thing Marianne's family of secret rogue witches wants.
But how much longer can the Pinhoes keep their secrets? Gammer, the leader of the clan, has gone mad, a powerful bad luck spell is wreaking havoc, and there's an unexplained plague of frogs. Not to mention the mysterious barrier Cat finds in the forest.
Marianne and Cat may be the only two who can set things right. But first Marianne must accept her own powerful magic, and Cat must uncover the secrets behind the mystical Pinhoe Egg.
Diana Wynne Jones
Diana Wynne Jones (1934–2011) was a British writer, principally of fantasy novels for children and adults, as well as a small amount of non-fiction. Some of her better-known works include the Chrestomanci series and the novels Howl's Moving Castle and Dark Lord of Derkholm.
Chrestomanci
Series contains 7 primary works and has 8 total works. Current series reading order on below.
Diana Wynne Jones herself recommends reading Charmed Life first, followed by The Lives of Christopher Chant. Then Conrad's Fate, Witch Week, The Magicians of Caprona and the short stories can be read in any order after that. The Pinhoe Egg is set soon after Charmed Life.
The Chronicles of Chrestomanci series includes Charmed Life and The Lives of Christopher Chant in Volume 1. Volume 2 contains Witch Week and The Magicians of Caprona, and Volume 3 contains Conrad's Fate ja The Pinhoe Egg.
Related series Chrestomanci (omnibus editions)