Muffler was a foundling, discovered as a baby in a hen's nest. Simon the farmer and his wife took the infant in, and as he grew older, he helped with the animals on the farm. But at night he is taken to a strange, different place by Grimbold, the big black mysterious cat, who wanted his help in rescuing Gareth, the sorcerer's son, from a particularly unpleasant spell.
Used availability for Nicholas Stuart Gray's Grimbold's Other World
March 1989 : UK Paperback
May 1986 : USA Mass Market Paperback
September 1978 : UK Paperback