Grace Livingston Hill 
The Substitute Guest [EPUB ebook] 

When Alan Monteith decides to help a friend in need by delivering a bottle of medicine to a sick woman, he never imagined being stranded in a blizzard. And he never imagined climbing a mountain on foot. But when his car breaks down in front of the Devereaux’s home, that’s just what he ends up doing. Daryl Devereaux was looking forward to a peaceful holiday until Alan Monteith arrives. As the young stranger and her brother trudge into the storm, Daryl is left to pray for their safe return, never realizing that night will change their lives forever.