This song is from A Walk To Remember, which was Mandy Moore’s biggest starring role until she got cast on This Is Us. If you haven’t seen A Walk To Remember, Mandy Moore plays a girl who marries Shane West but then dies a year later.
I guess this video is a sequel because now Mandy Moore is singing to Shane West from Heaven while Shane watches old home movies of him and Mandy goofing off between filming their scenes. Shane uses a telescope and discovers that he can see Mandy in Heaven and Mandy looks really happy. Then Shane goes into the city and is reminded that his romance with Mandy was just a part of a movie. I don’t know if that’s a happy ending or not.