Borderlanders - Gillian Polack

Some keys open doors to strange worlds...

Melissa has a happy marriage but her everyday life is a constant battle against pain. She discovers that her artwork can produce magic, prompting her to apply for an artist's retreat to a mysterious country house. Her old schoolfriends Bettina and Zelda are also at the same retreat. But neither the house nor their friendship is what they think. A mystical library, rapacious shadows, and keys to otherworldly rooms are the links to saving the house from destruction.

A unique fantasy about people whose stories, with all their oddity and excitement, seldom make their way into novels.