I am looking for a old mills and boon, the story is as follows:-
The heroine comes to stay at a rather grand farm where the hero lives; he lives there with the heroine's mother and his father, they had become stepbrother and stepsister during their teens when her mother and his father married. The heroine had gone away but returns to stay with them for a while. She has always looked up to him. I remember a scene where its raining and she is trying to shut a window when the man comes in. He tries to keep his distance because he has always felt responsible for her and thinks he shouldn't fall for her, but he has always been jealous of other guys and his resistance soon wears thin.
I seem to remember the cover of the book was dark blue (not totally sure about this though). The hero on the cover had brown/dark hair. I can't remember any characters' names.