STRANGER PASSING BY (Mills & Boon comics)

Crystal works at a boutique and must attend her company's Christmas party. She says yes when a charming man at the party asks her for a dance, but when the lights go out for a moment at the end of the song, he disappears. She later realizes that the man she was dancing with was the president of her company. And just two weeks later she finds herself butting heads with her dance partner!