Sentimental Hollywood nonsense. A film like this could be interesting, if it had some lifelike characters, fitting direction or some genuine emotion. Instead, you get Susan Sarandon, Julia Roberts, an extremely sentimental score and some kitschy drama. Then again, what would you expect from a Chris Columbus film.
Luke and Jackie are divorced, but Luke already has a new love in his life: Isabel. His kids don't really like Isabel as they see her as a replacement for Jackie. There's quite a bit of tension between them, until Jackie hears she has cancer. This changes their relationship, as time is running out for her.
Though the film is called Stepmom and there's plenty of potential drama there already, it wasn't quite enough for Columbus, so he introduced a character with cancer. It's a really odd turn of events that puts the film on an entirely different track, which just seems to underline that Columbus had no idea how to fill two hours of film with genuine, human drama. A very poor effort.