Blomkvist loses the libel case brought by billionaire Hans-Erik Wennerström and faces a prison sentence and damages.

Blomkvist steps down from Millennium and takes a leave of absence to protect the magazine from Wennerström's influence.

Henrik Vanger reveals his grandniece Harriet's mysterious disappearance and secretly hires Blomkvist to investigate, promising Wennerström evidence as payment.

Blomkvist settles into a cabin on Hedeby Island and begins reviewing decades of police case files on Harriet.

Blomkvist requests a research assistant for the investigation and Frode arranges to hire Lisbeth Salander.

Blomkvist's daughter Pernilla points out that Harriet's diary entries are Biblical citations rather than telephone numbers.

Salander identifies multiple murdered women whose gruesome deaths match the Biblical passages listed in Harriet's diary.

A mutilated and torched cat is left on the cabin porch as a warning to halt the investigation.

Blomkvist deduces from a family photo that Martin Vanger's red-patched jacket was the sight that frightened Harriet at the parade.

Blomkvist visits Martin's home under a pretext and is captured and beaten in a soundproof basement torture chamber.

Salander arrives at Martin's house and rescues Blomkvist from the basement torture chamber before he suffocates.

Martin drives his car into an oncoming truck and is killed while fleeing from Salander on her motorbike.

Blomkvist travels to Australia and finds Harriet alive on a sheep ranch, living under a false identity.

Salander reveals she hacked Wennerström's computer months earlier and gives Blomkvist a full copy of his hard drive.

Blomkvist publishes his exposé on Wennerström's corruption and returns to Millennium as a vindicated journalist.

Mikael Blomkvist's career collapses after losing a libel case to the billionaire Wennerström, prompting him to accept an unusual job from the elderly Henrik Vanger. Vanger believes a family member murdered his grandniece Harriet in 1966 and promises Blomkvist damning evidence against Wennerström as payment for solving the case. With the help of hacker Lisbeth Salander, Blomkvist connects Harriet's diary to a series of women's murders spanning decades. The investigation reaches its crisis point when Blomkvist confronts Harriet's brother Martin, a serial killer who captures him in a basement torture chamber before Salander intervenes and saves his life. Blomkvist eventually finds Harriet alive in Australia, and Salander's secretly hacked files on Wennerström give him everything he needs to rebuild his reputation. His published exposé returns him to Millennium in triumph and completes his full arc from disgrace to vindication.

The headline events of Blomkvist's fall, Harriet's case, and Wennerström's exposure.

Salander delivers her comprehensive background investigation report on Blomkvist to the lawyer Dirch Frode.

Salander breaks into Wennerström's apartment building and installs a device to access his computer remotely.

Blomkvist arrives at Hedeby and learns about the Vanger family's history of Nazism, eugenics, and domestic abuse.

Blomkvist visits retired detective Morell, who shares his enduring conviction that Harriet was murdered.

Berger visits Blomkvist in Hedeby and reveals she secretly negotiated a board partnership with Henrik Vanger for Millennium.

Cecilia ends her affair with Blomkvist after admitting she has developed genuine romantic feelings for him.

Salander meets Blomkvist for the first time when she shows up unannounced at his Stockholm apartment with bagels.

Blomkvist tracks down a couple who photographed the children's parade and obtains new images from that day.

Blomkvist is grazed by a bullet while jogging in the woods near Hedeby and barely escapes a sniper.

Salander traces Gottfried Vanger's presence to the locations and dates of several of the murdered women.

Blomkvist and Salander travel to London and arrange to have Anita Vanger's phone tapped to trace Harriet.

Harriet reveals her father sexually abused her and confesses to killing Gottfried on the day he drowned.

Harriet reunites with Henrik Vanger at the hospital, and he finally understands she has been sending him the pressed flowers.

Blomkvist discovers that the promised evidence against Wennerström is far too weak to be used against him.

Salander travels to Zurich in disguise and siphons $260 million from Wennerström's personal bank account.

While Blomkvist settles into Hedeby and pores over police files, Salander independently pursues her own leads on Wennerström's corruption back in Stockholm. Key supporting moments—including Berger's secretly negotiated partnership deal, Blomkvist's meeting with retired detective Morell, and his painstaking pursuit of parade photographs—slowly build the evidentiary foundation for the case. Salander meets Blomkvist for the first time and brings her formidable research skills to bear on identifying the full roster of serial murder victims connected to Harriet's list. After the truth about Martin's crimes is uncovered, Blomkvist and Salander follow Harriet's escape route through London to Australia, where she finally breaks her decades-long silence. The resolution is bittersweet when the promised Wennerström evidence proves worthless, but Salander has already prepared her own remedy. Her daring financial heist in Zurich ensures that Wennerström's empire will ultimately crumble.

The investigation's supporting moments and the parallel journeys of Salander and Blomkvist.

Holger Palmgren suffers a stroke and the exploitative lawyer Nils Bjurman is appointed as Salander's new guardian.

Bjurman sexually assaults Salander and threatens to have her institutionalized if she reports the attack.

Salander uses hidden camera footage of Bjurman's assault to blackmail him into surrendering full control of her finances.

Salander tases and restrains Bjurman, then tattoos a confession of his crimes across his abdomen.

Blomkvist realizes that Harriet's expression in a parade photograph shows fear, indicating she spotted someone disturbing across the street.

Blomkvist gains access to the Hedestad Courier photo archives and pieces together a chronological sequence of Harriet's final movements.

Henrik Vanger suffers a heart attack during the investigation and Frode takes over as Blomkvist's contact.

Salander climbs into Blomkvist's bed and the two begin a sexual relationship without defining it.

After being shot at in the woods, Blomkvist confronts Cecilia and demands she explain why she lied about Harriet's bedroom.

Blomkvist discovers that Cecilia and Anita wore identical dresses, revealing that Anita, not Cecilia, opened Harriet's window.

Salander burns Martin's murder binders and drops his laptop from a bridge into the water below.

Salander learns her mother has died and stays behind while Blomkvist travels to Australia alone to find Harriet.

Blomkvist and Salander agree to cover up the Vanger murders in exchange for Vanger donating to victims' families and crisis centers.

Wennerström is found shot dead in Spain after Salander anonymously tips off one of his many dangerous creditors.

Salander goes to confess her feelings to Blomkvist but sees him leaving with Erika Berger and throws away his gift.

This pool traces the pivotal decisions and discoveries that alter the course of both Blomkvist's investigation and Salander's personal life. Salander's guardianship crisis—Bjurman's assault, her act of revenge, and her reclamation of autonomy—runs parallel to Blomkvist's photographic breakthroughs that overturn long-held assumptions about Harriet's disappearance. Escalating threats like Vanger's heart attack and a bullet fired at Blomkvist in the woods raise the stakes and force both protagonists toward a dangerous reckoning with the truth. The discovery that Anita helped Harriet escape ultimately leads to the unmasking of Martin's crimes, and the violent aftermath forces Blomkvist and Salander into a morally uncomfortable cover-up agreement. Personal revelations punctuate the plot throughout, from Salander beginning a relationship with Blomkvist to her painful decision to walk away after seeing him with Berger. The novel closes not with triumph but with Salander alone, her feelings unspoken and her gift discarded in the trash.