Face in the Glass — Elizabeth Coldwell

Psychic Ceri is startled when her crystal ball starts showing her visions of a handsome man who isn't the boyfriend of her current client. Things become even stranger when the man's face appears in every reflective surface she looks into, and the visions become progressively more explicit, showing them making love. To solve the mystery, Ceri must visit the hall of mirrors when the fair comes to town, and use an ancient love spell to try to release the stranger from his bizarre captivity.