After receiving a well-earned certification from a sheltered boarding school, Carla Tate (Juliette Lewis), an ambitious and mildly mentally disabled young woman, returns home to her over-protective and slightly snobby mother Elizabeth (Diane Keaton). Elizabeth seems to act as if she is embarrassed about her youngest daughter's disability. During family discussions, Elizabeth adopts an uneasy attitude. Carla's father Radley (Tom Skerritt) is a dentist and recovering alcoholic. Carla's ambition is to seek more independence from her family by earning a diploma from a trade school. When Carla meets another mentally disabled student, Daniel McMann (nicknamed "Danny") (Giovanni Ribisi), they become friends and soon fall in love. Envying Danny's freedom, Carla convinces her parents she is capable of living on her own and moves into her own apartment. After a time, Carla and Danny become sexually active together.
Danny's independence is financially compromised when his wealthy and emotionally detached father abruptly stops sending subsistence money. Danny begins to realize that the independence he enjoyed comes with a staggering cost. Danny gets drunk, then seeks solace and insight (and a joyride in a vintage Ford Mustang convertible) from his landlord and friend, Ernie (Hector Elizondo).
During a Christmas party at the country club, Danny, nervous about his personal lot, drinks too much to build up his courage to declare his love for Carla. He is also telling everyone about their first time making love. A humiliated Carla bursts into tears, screaming at everyone to stop laughing at her. Although Daniel did not intend to embarrass Carla, she nonetheless refuses to see him. Over time, Carla realizes she still loves Danny and wants to see him again despite her mother's advising her otherwise. At her older sister Caroline's (Poppy Montgomery) wedding, Danny surprises Carla by showing up at the church and asking Carla to marry him, in a scene mimicking The Graduate, the couple's favorite film.
Everyone supports their wishes except Elizabeth, who is unsure Danny can take care of himself, let alone Carla, who becomes angry with her. Carla angrily tells her mother off that she is sick of her three behaviors: dominance, negativity, and doubt. Also, Carla is sick of her mother treating her like both an embarrassment and a handicap. Radley and her sisters Heather (Sarah Paulson) and Caroline support her decision, and the wedding is planned. At first, Elizabeth is determined not to attend. However, Radley admonishes her, saying he will walk Carla down the aisle and finally, she relents. Outside the church, Danny surprises Carla with a marching band playing a song from The Music Man... and they are chauffeured away to their honeymoon in Ernie's prized Mustang.Juliette Lewis as Carla Tate
Diane Keaton as Elizabeth Tate
Tom Skerritt as Dr. Radley Tate
Giovanni Ribisi as Daniel "Danny" McMann
Poppy Montgomery as Caroline Tate
Sarah Paulson as Heather Tate
Linda Thorson as Drew Evanson
Joe Flanigan as Jeff Reed
Juliet Mills as Winnie the Housekeeper
Tracy Reiner as Michelle
Hector Elizondo as Ernie
The Other Sister: Music from the Motion Picture was released on February 23, 1999. The lead song for the soundtrack was "The Animal Song" by Savage Garden. The music video for the song featured scenes from the film. It peaked at #109 on the Billboard 200 albums chart.
The Other Sister opened at #3 at the North American box office making $6,624,445 in its opening weekend behind Payback and 8mm, which opened at the top spot. It ultimately grossed $27,807,627 domestically, barely bringing back its $35 million budget, becoming a box office bomb.
The film received negative reviews from critics. On Rotten Tomatoes, the film maintains a 29% rating, based on 48 reviews, with an average rating of 4.7/10. The site's consensus: "Made-for-tv drama evokes anything but real emotion." Metacritic reports a 28 out of 100 rating, based on 21 critics, indicating "generally unfavorable reviews".
Roger Ebert rated the film at one out of four possible stars, and said the film was "so over-the-top maudlin that it makes Patch Adams and Stepmom look stoic and reserved."
Lewis was nominated for a Golden Raspberry Award for Worst Supporting Actress for her performance, where she lost to Denise Richards for The World Is Not Enough.