The Roving Heart — Marcia Miller

Gray-eyed Maggie Carter was a freelance dress designer, but she preferred to work for the Boutique Eldar, and her old friend, Brook Aldar. It was doubly damaging, therefore, when a design she had concocted appeared on the social scene under the name of Brook's chief competitor. It might have been a fantastic coincidence--but it was more likely that it was a clever piracy.

The incident with the dress was just one of a series of events that were shaking Maggie. Until she moved into a beach-house some miles from the city things had been smooth sailing, but her fiance, the amiable Tom Evans, a rising young lawyer, began to quarrel with her about the long drive to the beach-house. Maggie's plan had been to keep her apartment in the city, but then, somewhat unexpectedly, her roommate, usually so agreeable, told Maggie she was moving out.

It seemed to Maggie that all of her friends were deserting her just when she needed them the most, and she is beginning to think that those she thought were her enemies--especially the sarcastic Brad Weston--were really her friends. The answer to the puzzle is a surprising one, but when Maggie thinks about it, it all fits into place.