It’s bad enough that Jackie (Susan Sarandon) has to see her ex-husband (Ed Harris) take on a much younger girlfriend (Julia Roberts), but to see herself replaced in the motherly role is an even greater stab to the heart. Stepmom is obviously trying to address some real problems of modern family life by focusing on the rivalry between these two female characters, but they’re such extreme types it’s difficult to feel for either. Sarandon never forgets which days her children have soccer practice, or which shirt she should launder for her daughter to wear the next day. She’s a sewing diva who stitches Halloween costumes at a moment’s notice and Christmas “scrapbook” quilts out of mementos collected over the years. Roberts, on the other hand, oversleeps, forgets to pick up the kids at school, and even loses one of them in Central Park.

Like Chris Columbus’ other films (Mrs. Doubtfire, Nine Months), Stepmom provides many tear-jerking moments. Sarandon’s eyes are perpetually welled up. The movie’s finest moments occur when she’s struggling with her emotional losses. She’s already lost her man; can she hold on to her children? And can she accept Roberts into her already altered picture of happily-ever-after? These are meaty questions, but Gigi Levangie’s script robs the leading actress of the chance to explore them. Midway, Sarandon discovers that she’s dying of cancer. After her secret chemotherapy treatments fail, more tears are shed, and everyone has to resolve their issues double-time.

Roberts becomes a responsible stepmother, rushing to pick up the kids at school and putting her job as a fashion photographer in jeopardy. She starts bonding with the difficult daughter through rock songs and lipstick. And Sarandon has to let go of her jealousies, because, well, the chemo is making her too weak to fulfill her motherly duties. The film sags as it moves away from a portrait of divorce and remarriage towards a saccharin treatment about dying. “Are you scared?” asks the son of mom extraordinaire. “We can meet in your dreams,” she answers bravely.