Dennis, a 12-year-old boy, lives in an ordinary town with his 14-year-old brother John and their father, Dad, who is still reeling from the departure of his wife several years earlier. Dennis is a natural on the football field, one of the best on his team, and he clings to memories of his mother, especially her yellow dress, which he keeps in a photo. When he spots the same dress on the cover of a Vogue magazine at Raj’s corner shop, Dennis buys it, hoping to feel close to her. Dad’s reaction is scathing: the magazine must be thrown away, and Dennis endures taunting from John, who calls him “Denise.”
At school, Dennis’s day takes a sharp turn when he earns detention for kicking a football through an office window. In that quiet hour, he meets Lisa James, a girl who is widely regarded as the most fashionable student. Lisa invites him to her home, where she shows off a collection of Vogue magazines and, boldly, dresses Dennis in women’s clothing. The following week, they decide to venture out in public, with Dennis presenting as “Denise,” a French exchange student who speaks little English. They head to Raj’s shop, where Raj mistakes Dennis for Denise. Their charm continues to grow as they meet Mac, a friend of Lisa’s, who, unaware of the truth, asks Denise on a date. With this growing success, Dennis accompanies Lisa to school the next day, this time in the guise of Denise.
In French class, Dennis struggles with the language on the teacher’s side and ends up awkwardly criticizing the teacher’s accent, a misstep that deeply upsets Lisa. During a break, a kicked ball hits Dennis, and his wig falls off, triggering an angry response from Mr Hawtrey. Dennis is expelled for cross-dressing, and Dad’s anger boils over as he confines his son to his room. The tension peaks when Dad confronts Dennis, demanding the half-burned photograph of Dennis, John, and their late mother, which Dennis reluctantly hands over. Darvesh, Dennis’s best friend, stops by but is sent away by Dad. Left alone, Dennis spends the day in his room until Lisa climbs to his window and promises to help him regain his place at school.
Darvesh’s encouragement nudges Dennis back toward the game, and he heads to the field anyway. Maudlin Street, the rival team, has dominated the trophy for three years and is known for rough play. Dennis learns that without him—the team’s star striker—they’re far behind, already down 6–0. At halftime, Lisa gives a signal and opens the changing room to reveal all the boys from Dennis’s school wearing Lisa’s dresses. The game resumes with the entire team in dresses, and Dennis quickly scores two goals, feeling a joy he has never experienced before. The score climbs, and the team claws its way back from a 6–0 deficit to 6–6, inching toward victory—until one Maudlin Street player injures Dennis. His father appears in the stands, cheering him on, and the game ends in a hard-won win for the school. Although Mr Hawtrey remains determined to expel Dennis, his father steps in to defend him, securing his readmission.
After the match, Dennis returns the dresses to Lisa and thanks her for opening his eyes. He hesitates to confess his deeper feelings for Lisa, choosing instead to say, “I’ll tell you when I’m older.” On the walk home, Raj drops a surprising hint: Mr Hawtrey’s sister, Miss Doris, is the purchaser of the Telegraph, and there is something “funny” about her. The next morning at Raj’s shop, it’s revealed that Miss Doris is actually Mr Hawtrey cross-dressing in a skirt. Faced with this discovery, Lisa and Dennis threaten to reveal the secret unless Dennis is readmitted to the school. Mr Hawtrey yields, and Dennis, his father, and his brother begin to rebuild what they’ve lost.
With the family healing, Dennis and his father grow closer, Dennis and Lisa stay friends, and John becomes more protective of his younger brother.
In the BBC adaptation, the story pivots to Christmas. Darvesh and his mother visit Dennis’s home, but only Darvesh passes inside. Darvesh’s mother, Jaspreet Kaur, flirts with Dennis’s dad, and the two share a kiss, adding a lighter, festive note to the season as they all celebrate together.
Jaspreet is a key figure in the adaptation, and the family’s holiday reunion adds a warm, hopeful coda to the tale. The evolution of Dennis’s world—from fear and disguise to acceptance and connection—remains central to the story, underscored by the supportive, sometimes complicated, bonds of family and friendship.
