In the early 1950s, sixteen-year-old Lynda Mansell Emily Lloyd lives in a small English seaside town with her widowed father Hubert Mansell Geoffrey Hutchings and younger sister Margaret. Feisty, outspoken, and unapologetically bawdy, Lynda uses dramatic, crowd-pleasing stunts on the promenade—biking with her skirt hiked up and inviting young men to compare her legs to Betty Grable's—and a sharp tongue that scribbles insults like
> Up yer bum
> Cock Off
which sets her apart from peers and even her sister. Her father runs a barber shop and cannot easily rein her in, trying various jobs for her at a hair salon, a bus depot, and a fish-and-chip van, only to watch each role crumble.
After a moment of introspection via brief flashbacks that hint at a close relationship with her late mother, Lynda begins to explore intimacy with two boys: Brian Lee Whitlock on the promenade and Dave Jesse Birdsall, a bus conductor. She loses her virginity to Dave, but grows tired of Brian's immaturity, while Hubert warns off Dave without telling Lynda. Amid this, Eric Tom Bell, a back-street bookie who knows Hubert, shows interest in Lynda. At first she resists his crude advances, but as her home life grows tenser, Lynda finds herself sleeping with Eric. When Hubert learns of the relationship, he confronts her with shame and sorrow, lamenting how he believes her mother would have felt if she were alive.
Lynda leaves home to live with Eric, but the relationship proves hollow—he offers no comfort in her moment of need and treats her more as a sexual object than a partner. After that painful episode, Lynda accepts a job as a waitress at a tea room and hopes for a different kind of life. Yet Eric reappears, claiming to miss her, only to drop the pursuit when she reveals she is pregnant. Faced with pregnancy in a still-restrictive era, Lynda contemplates an illegal abortion but realizes she cannot afford it.
Hubert learns of his daughter's pregnancy and travels to the tea room to speak with her. The confrontation becomes a public scene: Lynda escalates into a tirade from atop a table, declaring that she likes sex and railing against society's reluctance to discuss it, while slinging insults at the customers. The outburst costs her the job, though a few customers applaud her honesty.
Aunt Millie Pat Heywood steps in, advising Lynda about the options—an abortion or putting the baby up for adoption—emphasizing that the choice belongs to her, while offering money for an abortion. Lynda makes her way to an abortionist's house but hesitates at the doorstep, glimpsing an old man and a little girl who remind her of what she could lose.
In the end, Lynda returns home by bus, entering a world she thought she’d left behind. She passes the places she once haunted, including the promenade, and in a striking act of resolve, pushes a pram containing her baby across a bowling green where Eric and others play. The film closes on a quiet, hopeful note as she rings Hubert’s doorbell and cradles her newborn, signaling a new chapter that begins with acceptance and responsibility.
