The film unfolds through 36 distinct chapters, set in the fictional Irish town of Tyrellin, which borders Northern Ireland during the late 1970s. The story is narrated by animated cartoon robins, introducing us to Patrick Braden, whose mother, Eily Bergin, makes a heart-wrenching decision to leave him on the doorstep of the local parochial house, home to his father, Father Liam.
As Patrick grows, he finds himself placed with a foster mother who shows him little affection. Struggling with his identity, he is seen experimenting with dress and makeup, much to the dismay of his foster family. However, he finds solace among his close friends: Charlie, Irwin, and Lawrence. Notably, Lawrence's father even likens Eily to the glamorous American movie star Mitzi Gaynor, seeing a resemblance that draws Patrick closer to his roots.
In his late teens, Patrick's rebellious spirit surfaces as he stirs controversy at school for writing provocative stories about his conception and expressing a desire for a sex change. Embracing his true self, Patrick transitions, adopting the name Kitten, sometimes referred to as Patricia. Despite seeking guidance from Father Liam during confession about Eily, he finds himself rebuffed and alone.
Determined to escape his troubled life, Kitten hits the road with a glam rock band called Billy Hatchet and the Mohawks. Here, she develops a crush on the charismatic leader, Billy, who provides her temporary shelter in a trailer. Unfortunately, she soon discovers he is entangled with the IRA, hiding firearms in their mobile home.
Meanwhile, Irwin's involvement with the IRA strains his relationship with Charlie, who is distressed over the escalating danger. Kitten, indifferent to the politics surrounding her, changes her viewpoint after losing Lawrence to a police action following a botched IRA operation. In a moment of defiance, she discards a cache of guns into a lake, signaling a shift in her stance on violence.
When Billy decides to leave, fearing for his safety, Kitten finds herself abandoned and must confront the harsh reality on her own. She travels to London seeking Eily, but her initial attempts yield no results. Homeless and desperate, she takes refuge in a small cottage within a park, only to discover it is part of a whimsical children's theme park based on The Wombles.
To make ends meet, Kitten takes a job as a singing and dancing Womble, but her stint is short-lived as chaos ensues when a co-worker attacks their supervisor. During a harrowing turn of events, Kitten faces violence while working on the streets but cleverly escapes a near-fatal encounter by using her perfume—Chanel No. 5—as a weapon.
One day, at a diner, she crosses paths with magician Bertie Vaughan, who is intrigued by her notebook. During their conversation, she reveals her story about "The Phantom Lady," someone lost in the sprawling city—ultimately a metaphor for her connection with her estranged mother. Bertie offers her a role as his assistant, transforming her narrative into a spectacular hypnosis act.
As their relationship deepens, Bertie tries to express his affection, only to learn that Kitten identifies as transgender. Soon after, Charlie finds them together, leading to a rift in Kitten's newfound happiness.
Kitten then visits a club frequented by British soldiers, where a bombing orchestrated by the IRA results in yet another traumatic experience—this time, an arrest as a suspected terrorist. Subjected to inhumane treatment, she pens a dramatic statement, which is later illustrated in a comedic fantasy film spoof, depicting her innocence in a world fraught with conflict.
With nowhere to turn after being released, Kitten attempts to find stability but is once again drawn to the streets. Fortunately, one of her interrogators comes to her aid, bringing her to a peep show where she undergoes a striking transformation into a blonde. In a turning point, Kitten's estranged father appears, echoing sentiments expressed in the confessional, and gives her the key to locating Eily.
Disguised as a telephone company researcher, Kitten discovers her younger half-brother, also named Patrick, before finally meeting Eily. In a moment of shock, she faints upon seeing her mother but later regains consciousness, choosing not to reveal her true identity during their encounter.
After Irwin's tragic death at the hands of the IRA, Kitten returns home to care for a pregnant Charlie, striving to reconnect with her father, the priest. Their living arrangement sparks outrage within the town, culminating in a violent firebombing of the parish house, forcing Kitten and Charlie to escape to London for safety.
In the poignant closing scene, they encounter a pregnant Eily alongside the little Patrick at a medical office, where Charlie is receiving postnatal care. Though Kitten greets them warmly, she continues to keep her identity a secret, leaving their reunion suspended in bittersweet uncertainty.
