The Christmas Bride — Grace Livingston Hill

When Greg Sterling glances out his hotel window one bleak afternoon, he is startled to see a young woman slip from the park bench where she has been sitting and fall in a crumpled heap on the ground! He races to the woman's aid and vows to help her overcome her desperate circumstances.

Soon, though, he realizes his interest in Margaret is much more than that of a mere benefactor. Captivated by her ethereal beauty and indomitable spirit, Greg acknowledges to himself that he is falling in love. But before he can share his feelings with Margaret, she disappears without a trace!

Now all that matters to Greg is finding the woman he loves....