"The Master" is a short story by Diana Wynne Jones
Synopsis
A vet is called out in the early hours of the morning to a strange location in the middle of nowhere. After being chased by wolves a strange man shows her around the Master's house and she tries to understand who the Master is and why he keeps wolves.
It is in several short story collections: Everard's Ride, Minor Arcana, Believing Is Seeing, Hidden Turnings and Unexpected Magic.