In Stockholm, Sweden, the tale begins with journalist Mikael Blomkvist, played by Daniel Craig, who finds himself reeling from the fallout of a libel case against the corrupt businessman Hans-Erik Wennerström (Ulf Friberg). Blomkvist, a co-owner of the influential Millennium magazine, is offered a lifeline by the wealthy magnate Henrik Vanger (Christopher Plummer), who tasks him with solving a mystery that has haunted him for over four decades: the disappearance and presumed murder of his great-niece Harriet Vanger.
To gain valuable information on Wennerström, Blomkvist accepts Vanger's challenge, plunging into the dark history surrounding Harriet's vanishing in 1966. The Vanger family, dysfunctional and steeped in secrets, had gathered on a remote Swiss island for their annual board meeting during which Harriet vanished without a trace. With an accident blocking the only bridge, Blomkvist quickly learns that one of the family members may be her killer.
Meanwhile, Lisbeth Salander (Rooney Mara), an exceptional but troubled hacker, is conducting her own research on Blomkvist for Vanger. Salander, under the guardianship of the manipulative lawyer Nils Bjurman (Yorick van Wageningen), endures his abusive tactics until she takes back her power in a shocking confrontation. Using her formidable skills and her unique perspective on the world, Salander becomes a key ally in Blomkvist's investigation into Harriet's case.
Blomkvist immerses himself in the Vanger family history while staying at their estate, where he learns of the dark ties some family members have had with extremist ideologies, including past affiliations with the Nazi Party. The revelations lead him to discover clues hidden within Harriet's possessions, including a notebook containing names and numbers that have eluded deciphering for years.
As Blomkvist digs deeper into Harriet’s life, he starts to uncover a disturbing pattern linked to a series of murders involving young women with Hebrew names, leading him to suspect that Harriet’s disappearance may have been motivated by anti-Semitism. His investigation is fueled by passionate collaboration with Salander, whose research skills uncover significant evidence connecting Harriet's case to a larger series of unsolved crimes.
Their dynamic evolves from a professional partnership into a romantic relationship, sprinkled with moments of intensity and mutual respect. However, danger looms as Blomkvist becomes a target, when he unexpectedly finds himself in Martin's (Stellan Skarsgård) sights, Harriet's brother who now heads the Vanger company. The tension culminates in a dramatic clash, with Salander coming to Blomkvist's rescue.
In a twist of fate, Blomkvist ultimately deduces that Harriet might still be alive, hidden under a new identity orchestrated by her cousin, Anita (Joely Richardson), who had tried to help her escape a harrowing childhood. This revelation leads to a poignant reunion between Harriet and Henrik, as past traumas find resolution.
As the narrative unfolds, Blomkvist and Salander confront Wennerström, and what was initially promised as incriminating evidence against him turns out to be misleading. Salander's technological prowess surfaces once more as she infiltrates Wennerström's digital life, exposing his nefarious dealings. The fallout is swift and severe, marking the collapse of Wennerström’s empire, leading to his ultimate fate.
Yet, amidst the chaos of revealing truths and settling scores, a bittersweet conclusion awaits Salander, who grapples with her feelings for Blomkvist as she witnesses him with his long-time partner, Erika Berger (Robin Wright). Torn between love and circumstance, she must navigate the complexities of her emotions, leading to a poignant and reflective end.
In this riveting tale of intrigue, passion, and revenge, the interplay of personal demons and familial secrets drive the narrative forward, culminating in a gripping exploration of the lengths one would go to uncover the truth.
