The Grail and the Ring(1994)
(The second book in the Kingdom of Celydonn series)
A novel by Teresa Edgerton
The rune-carved ring of an ancient mummy catapults Gwenlliant of Celydonn and her infant son into the Shadow realm, where a monster stalks the children of Celydonn.
Used availability for Teresa Edgerton's The Grail and the Ring
January 1994 : USA Mass Market Paperback