Harriet decides to attend the Gaudy Night reunion and drives to Shrewsbury College to reconnect with academia.

Harriet finds a disturbing obscene sketch of a naked woman attacking a scholar dropped on the quad flagstones.

Harriet discovers a poison-pen note calling her a murderess stuffed into her academic robe pocket.

The Dean writes to Harriet requesting help with an outbreak of poison-pen letters and vandalism at the college.

Harriet returns to Shrewsbury and learns the vandal has burned academic gowns and defaced Miss Lydgate's manuscript.

Harriet and Pomfret discover a hanging effigy wearing a scholar's robe with a knife pinned through its chest in the Chapel.

The Poison-Pen causes a nighttime blackout rampage, smashing lamps and throwing books through windows across the college.

Miss Newland is rescued from the river after attempting suicide following dozens of letters suggesting she is losing her mind.

Harriet enlists a mutual friend to get an urgent message to Wimsey, who is abroad on Foreign Office business.

Wimsey arrives in Oxford, investigates the Science-Lecture room with a fingerprint kit, and finds hairpins linked to Miss de Vine.

Wimsey dines with the Shrewsbury faculty and wins their trust through wit, charm, and intellectual range.

During the faculty dinner, Miss de Vine recounts how she exposed a male academic named Robinson for fraud, ruining his career.

Harriet is choked by an unseen attacker in Miss de Vine's darkened room and suffers a head injury.

Wimsey presents evidence to the assembled faculty identifying Annie as the Poison-Pen and as Robinson's widow.

Wimsey proposes to Harriet in Latin on Magdalen Bridge, and Harriet accepts in the same language.

Harriet Vane returns to her beloved Shrewsbury College for a Gaudy Night reunion, where she stumbles across disturbing evidence of a bitter campaign targeting female scholars. Called back to investigate months later, she faces escalating vandalism and anonymous letters that culminate in a student's attempted suicide. Unable to solve the case alone, Harriet reluctantly reaches out to Lord Peter Wimsey, who infiltrates the college and draws out a crucial clue from Miss de Vine about a ruined academic named Robinson. The trail leads to Annie, a college scout and Robinson's widow, who blames the female scholars for destroying her husband's career and leaving her family destitute. With the mystery solved and Annie taken into custody, both Harriet and Wimsey are freed from the emotional barriers that have kept them apart for years. They finally become engaged on Magdalen Bridge in a quietly triumphant ending.

The headline events of the Poison-Pen investigation and Harriet's love story.

Harriet reconnects with Miss Lydgate and meets the formidable historian Miss de Vine at the Gaudy Night festivities.

Miss de Vine compliments Harriet after the Gaudy dinner on being true to herself despite others' expectations.

Harriet catches Pomfret scaling the Shrewsbury wall while attempting to return a very drunk Miss Cattermole to campus.

Harriet lectures Cattermole about her responsibilities as a student after helping her home drunk the night before.

Harriet overhears Jukes attempting to blackmail Pomfret about the wall-scaling incident and sends the dismissed porter away.

Harriet collides with Wimsey's nephew Viscount St. George outside Christ Church Cathedral while returning from a church service.

Harriet learns Jukes has been arrested for stealing items she had previously blamed on the Poison-Pen.

St. George is found by Harriet in the infirmary after crashing his car while racing to beat college curfew.

St. George reveals he once encountered a deranged woman inside Fellows' Garden who threatened to murder him.

The Poison-Pen scrawls 'Ha, Ha' on the Senior Common Room walls, deepening suspicion and fraying tempers among the faculty.

The University Vice-Chancellor receives a poison-pen letter insinuating strange and scandalous behavior at Shrewsbury.

Harriet receives a suspicious fake phone call urgently summoning her back to the college alone at night.

Wimsey and Harriet spend over an hour haggling for an antique chess set and then play music together on an antique spinet.

Harriet's chess set is found smashed in her room and she confronts Miss Hillyard over the broken pieces stuck to her shoe.

Annie is brought before the assembled faculty, confesses freely, and vents her hatred of female intellectuals.

Alongside the central mystery, a vivid cast of secondary characters generates complications, clues, and comic relief that drive the story forward. Harriet's encounters with reckless students — Pomfret, Cattermole, and Wimsey's irresponsible nephew St. George — each yield unexpected consequences that intersect with her detective work. The crooked porter Jukes muddies the investigation until his arrest clarifies which crimes were his and which belonged to the true vandal. As the Poison-Pen grows bolder, the college's atmosphere of suspicion deepens until the Vice-Chancellor himself receives a threatening letter and tempers fray openly in the common room. A fake phone call lures Harriet into a near-ambush, and the smashing of her prized chess set reveals new evidence about the culprit's hatred. The pool closes with Annie's dramatic confession before the assembled faculty, laying bare the class resentment and grief that fuelled every attack.

The supporting cast and secondary incidents that shape the investigation.

Harriet posts her Gaudy Night acceptance form after long deliberation about facing her scandalous reputation at the college.

Harriet reflects on her three-year inability to either accept Wimsey's proposals or permanently end their connection.

The New Library is found vandalized with graffiti and books flung from shelves, timed to embarrass the college before the Chancellor's visit.

Harriet has a conversation with Miss de Vine about following one's deepest desires above all other competing interests.

Wimsey's annual April Fools' Day marriage proposal arrives late but treats Harriet as a full intellectual equal for the first time.

Harriet sends Wimsey a reply letter admitting she would welcome his help, surprising both herself and him.

Harriet spots an unknown young woman leaning dangerously far over the parapet of the Magdalen College tower.

Harriet realizes the girl from the tower is the academically gifted Miss Newland when they meet during the School Sweeps draw.

Pomfret proposes marriage to Harriet, who declines gently but is secretly pleased by his attention.

Harriet admits to herself on the riverbank during their punting trip that she has long been in love with Wimsey.

Harriet discovers that Wimsey read and completed her unfinished sonnet from her case file, revealing his own emotional vulnerability.

Harriet writes a secret love note to Wimsey and tucks it in her pocket in case she is found dead that night.

St. George spots the same strange woman on Magdalen Bridge in broad daylight, looking deranged and muttering to herself.

Miss de Vine counsels Harriet after Annie's outburst to stop hurting herself and others by remaining undecided about Wimsey.

Wimsey confesses to Harriet that his early pursuit of her was arrogant and self-absorbed, showing genuine humility.

Gaudy Night traces Harriet's gradual emotional awakening through a series of revelatory moments that parallel the poison-pen investigation. From her initial hesitation about attending the reunion to her growing recognition of her feelings for Wimsey, each turning point nudges her closer to an honest reckoning with herself. Key conversations with Miss de Vine and Wimsey's unexpectedly egalitarian proposal letter challenge her long-held belief that intellect and romance are incompatible. Near-tragedy, a completed sonnet, and a terrifying nocturnal walk each strip away another layer of her emotional defenses, while the case itself clarifies the devastating human cost of rigid principles without mercy. By the time Annie's arrest releases the tension at Shrewsbury, Harriet has fought through years of self-doubt to reach an honest answer. Wimsey, having confessed his own past arrogance, is finally worthy of it.

The pivotal decisions and emotional discoveries that define Harriet and Wimsey's relationship.