Shortly before embarking on her senior year of high school, Darcy Elliot (Molly Ringwald), an aspiring journalist, sneaks away for a weekend road trip with her devoted boyfriend, Stan Bobrucz (Randall Batkinoff), to check out her potential college, the University of Wisconsin in Madison. Thrilled to have some time alone, Darcy and Stan stop by the roadside, where they share an intimate moment together.
Later, with hopes of writing for the school newspaper, Darcy meets with the student editors on campus. Despite their initial dismissal of her articles regarding her hometown of Kenosha, Wisconsin, they acknowledge her enthusiasm and encourage her to send more samples. That evening, as the couple sets up a tent to camp and indulges with a glass of wine, they toast, > "To forever." Yet, Darcy harbors private doubts about the future of their relationship, especially since Stan intends to apply for an architecture scholarship at the California Institute of Technology.
Fast forward two months, and Darcy finds herself feeling nauseated at the sight of food, leading her to suspect she might be pregnant. While Stan remains supportive, tensions rise between Darcy’s single mother, Donna Elliot (Miriam Flynn), and Mr. Bobrucz (Kenneth Mars)—Stan’s religious father—as they argue fiercely over whether Darcy should consider abortion or adoption. Concerned that an unexpected pregnancy could disrupt her college dreams, Donna books an abortion appointment for her daughter. However, Darcy ultimately chooses to raise her child with Stan instead.
Excited yet apprehensive about starting a family, the couple decides to wait until Christmas to reveal the news to their parents. When they finally do, they are met with outrage from Mr. Bobrucz, who attacks Darcy’s honor, resulting in a fierce confrontation between the young couple and their families. Estranged from their parents, Darcy and Stan opt for a simple life by moving into a rundown studio apartment and getting married in a quaint church ceremony.
With Stan taking a job as a shoe salesman, a guidance counselor suggests that Darcy drop out of high school, claiming it could set a poor example for her peers. Appalled by the suggestion, Darcy ultimately decides to enroll in night classes while working day shifts at a hamburger joint. Meanwhile, Stan receives a full scholarship to Caltech, but learns that the institution does not accommodate housing for married freshmen. Rather than revealing the truth to Darcy, he pretends he wasn't accepted.
On prom night, Darcy goes into labor and delivers a baby girl, whom she insists on having her mother notified. Amidst the chaos, Donna arrives with an adoption liaison, hoping to persuade Darcy to reconsider keeping the baby. After seeing her granddaughter, Donna decides to support Darcy, but their relationship is strained as Darcy battles postpartum depression. Although Darcy struggles with maternal instincts, Stan embraces fatherhood and lovingly names their daughter Theodosia after his grandmother.
One night, while Stan is at work, Darcy spots a man lurking outside their apartment and calls 911, fearing for her and Thea's safety. The police identify the intruder as Mr. Bobrucz, who seeks to reconnect with his estranged son, Stan.
As financial burdens escalate, both Darcy and Stan confront the fact that they may never be able to attend college. When Thea falls ill and they can’t afford medical expenses, Darcy resolves to move back in with her mother, which puts additional strain on their relationship. Stan begins to drink heavily and sneaks out at night, eventually crossing paths with his former girlfriend, Michaela (Michelle Downey), who tries to turn him against Darcy by blaming her for ruining his aspirations. However, in their conversation, Stan recognizes that his love for Darcy transcends all else.
After learning the truth from Michaela that Stan wasn't accepted at Caltech, an overwhelmed Darcy contacts the university and discovers that another scholarship has become available. Enrolling Stan without his consent, she pretends to have moved on, kicks him out, and seeks an annulment for their marriage since they were both underage at the time of their wedding. Despite briefly contemplating attending Caltech, Stan soon understands that Darcy orchestrated their separation and pleads with her to reconsider.
During Darcy’s night school graduation, Stan surprises her by announcing that they’ve both received scholarships to the University of Wisconsin after he submitted a heartfelt piece Darcy wrote about the struggles of young motherhood to the editor of the school newspaper. Even though Donna advises Darcy to abandon the relationship, she ultimately decides for herself. In a beautiful moment of reconciliation, Stan asks Darcy to marry him once more, pledging their future together.
