On a Gentle Breeze

Kaila McDonnell left on what was meant to be a working holiday before going to University. One year away was what she had committed. On the night of her planned 'Welcome Home' party she does not appear - but when she does, they find the Kaila who left them for a year's working holiday is not the same one who returns. Is this their daughter and sister? What is the secret she is hiding? And why won't she discuss where she was, and what she was doing?