As Carla Tate returns home after her time in a protective boarding school, she faces the stifling environment created by her overbearing parents. Her mother, Elizabeth, comes across as awkwardly embarrassed, as if Carla’s mental disability is a source of shame for the family. The tension within their household simmers beneath the surface, particularly when the past, including Carla's experiences with bullying, is brought to light. Meanwhile, her father, Radley, a dentist and recovering alcoholic, remains emotionally distant and disconnected from the family's struggles.
Driven by a strong desire for autonomy, Carla dreams of gaining independence through education at a polytechnic school. She unexpectedly forms a close friendship with Daniel McMahon, affectionately known as "Danny." Together, they share aspirations of self-reliance, and their bond soon evolves into romance. Fueled by newfound confidence, Carla decides to move into her own apartment, much to her parents' alarm.
However, Danny's journey toward independence comes with significant challenges when his affluent father suddenly withdraws financial support due to Danny's academic difficulties. This reversal forces Danny into a world of uncertainty. Seeking comfort, he turns to his friend and landlord, Ernie, as he embraces the liberating experience of his vintage Ford Mustang convertible.
As the holiday season draws near, Danny's insecurities surface during a Christmas party at a country club. Desperate to confess his feelings to Carla, he finds himself hindered by his excessive drinking, leading to a vulnerable moment where he accidentally reveals intimate details of their relationship, causing Carla deep embarrassment and heartache.
Following this event, Carla resolves to end their relationship, despite her true feelings for Danny. It isn't until he realizes the depth of his love for her at her sister Caroline's wedding that he decides to take a bold step to reclaim her heart. In a stunning moment reminiscent of their favorite film, The Graduate, Danny unexpectedly interrupts the ceremony, proposing to Carla and compelling her to say yes.
The narrative weaves through this bittersweet tale of unreciprocated love, exploring the thin line between vulnerability and independence as Carla and Danny strive to understand their place in the world of adult relationships. As wedding preparations ramp up, Carla, along with her supportive sisters Heather and Caroline, finds an unexpected ally in Radley, who stands up against Elizabeth's disapproval. Elizabeth, initially convinced that Danny is incapable of caring for himself, begins to grapple with her own motivations and perceptions.
Fueled by her sisters' encouragement, Carla gains the courage to confront Elizabeth's negative attitude and crippling self-doubt. In a pivotal moment, Radley warns Elizabeth that he will escort Carla down the aisle if she opts out of attending her daughter's wedding. After some deep reflection, Elizabeth ultimately comes to terms with her mistakes, finding happiness in supporting her daughter's new chapter.
When the big day finally arrives, Danny pulls out all the stops for a memorable celebration. A surprise performance by their school's marching band performs "76 Trombones" from The Music Man outside the church, filling the atmosphere with an infectious joy. As Carla and Danny exchange vows and set off on their honeymoon, they do so in style, driven away in Ernie's beloved Mustang – the perfect send-off into their new life together.
