The Sentinel recap

Jack Reacher intervenes when an organized team tries to abduct Rusty Rutherford, a fired town IT manager blamed for a ransomware disaster. Rutherford's experimental Cerberus system preserved an archive and a malware fragment on eight discarded servers. Reacher, Sarah Sands, and Rutherford recover the equipment and learn that Russian operatives want an old record capable of exposing their asset at Oak Ridge. Henry Klostermann, owner of a former Soviet spy house, buys a clone while secretly assisting the cell and organizing a neo-Nazi rally. The Russians forge a record to conceal Klostermann's daughter, Diane Smith, but the original exposes her and the FBI detains her. Reacher rescues undercover Agent Fisher from Klostermann's bunker, where Klostermann admits murdering journalist Toni Garza and ordering Marty's death. Klostermann dies, and John Goodyear is exposed as his Brotherhood collaborator. Rutherford regains the town's respect, Officer Rule pursues Goodyear's vacant post, and Reacher leaves toward Nashville.

Previously: Jack Reacher is an itinerant former military police officer who travels without a fixed destination.

After making a dishonest Nashville bar owner pay a band's withheld fee, Jack Reacher travels on and reaches a town crippled by a ransomware attack. He interrupts an organized attempt to abduct Rusty Rutherford, the former town IT manager blamed for the disaster. The police arrest Reacher and Rutherford instead of pursuing the fleeing team. Detective John Goodyear dismisses the danger and tries to send Reacher away, while a remote controller using the name Speranski orders renewed efforts to seize Rutherford. Rutherford explains that his unfinished defense system, Cerberus, failed along with the town's backup, though he believes an old laptop will prove that he warned his superiors. A federal investigator calling himself Jefferson Wallwork questions Reacher about whether Rutherford hid some small object and asks him not to alert Rutherford. Reacher agrees to leave only after receiving a promise of protection. Marty, the former officer assigned to drive him out, instead heads for an abandoned gas station. Reacher discovers that an unknown blackmailer ordered Marty to deliver him to an ambush and controls a local network tracking Rutherford. He restrains Marty and stays to confront the threat.

Reacher avoids the gas-station trap, uses Marty's phone and car against the pursuing group, and finds Rutherford after a failed attempt to flee. Rutherford chooses to remain in town and asks Reacher for help. Their inquiry connects the ransomware crisis to Toni Garza, a murdered journalist who had sought Rutherford's assistance with historical property records. Reacher also uncovers a separate local effort to obstruct the insurance negotiation and turns Holly's apparent abuser over to the police. Officer Rule quietly helps him examine the connection to Garza. Reacher and Rutherford hide in an absent neighbor's apartment while Speranski restores surveillance and orders Marty killed. Reacher observes the operatives attaching a tracker to Rutherford's car and removes two members of their external team without learning what they seek. Sarah Sands then arrives. Rutherford identifies her as a former Bureau colleague who helped him build Cerberus. Sands explains that the system preserved the town's backups and captured part of the ransomware malware, potentially identifying the attackers and giving Cerberus commercial value. Rutherford then reveals that he discarded the eight servers on which it ran, making the missing array the likely object of the pursuit.

Rutherford and Sarah Sands enter the town IT building while Reacher diverts the surveillance team. They recover Rutherford's laptop but discover that the eight-server cabinet is gone. A copy of Toni Garza's case file leads them to Henry Klostermann, a retired municipal contractor who owns a former Soviet spy residence that Garza had researched. Klostermann says he hired her for family-history work and offers Rutherford cash for first access to an older archive server, but Reacher concludes that he is concealing his true interest in the records. At a separate rendezvous, Reacher meets Special Agent Fisher, an FBI operative undercover within the Russian cell. She explains that the Sentinel protects election-system software across 48 states and that Russia wants it to undermine confidence in elections. The cell caused the archive fire and ransomware attack because a surviving physical record could expose an active Russian agent. Jefferson Wallwork is Fisher's FBI partner operating under a Homeland Security cover. The cell had planned to seize Rutherford, recover the record, and stage his death as suicide. Fisher warns that a specialist from Moscow will arrive after a brief surveillance-only window, leaving Reacher two days to locate the discarded archive server.

Reacher keeps the Sentinel operation secret from Rutherford while he, Sands, and Rutherford trace the missing servers through the town's waste contractor. Recycling records identify Dave Tomasino as the driver for both relevant collections, although the equipment never reached the recycling center. Sands initially questions whether Reacher engineered the danger to win Rutherford's trust, but decides to continue working with him while remaining cautious. When confronted, Tomasino explains that threats against his pregnant wife forced him to leave his unlocked truck beside Fat Freddy's diner so valuable electronics could be removed. He confirms that the server cabinet disappeared during one of those stops and identifies diner owner Bill Budnick as the man enforcing the arrangement. Reacher's group finds the empty cabinet in a locked outbuilding at the diner. Budnick admits both an extortion arrangement with a protection racket and his own threat against Tomasino's family, then directs them to a storage unit. His information contains a transposed number, but Reacher corrects it. In the actual unit, a large cache of stolen electronics includes all eight missing servers. The group loads them into its minivan along with compatible hardware for making copies, although the archive data has not yet been tested.

At a concealed motel workroom, Rutherford confirms that the archive scans survived intact and that Cerberus is damaged but recoverable. After Reacher explains the Sentinel threat, Rutherford creates two archive clones. Jefferson Wallwork receives one for FBI analysis, while Reacher sells another to Henry Klostermann as bait. Klostermann pays $15,000 and insists that Rutherford retain no copy, but the Russian operation does not stop. Reacher also learns that Klostermann lied about when his father entered the United States and is organizing an invitation-only April 20 rally for a white-supremacist Brotherhood. Zach, a biker considered for the rally's security, confirms that recruits are expected from every state. Reacher forces Zach's group to resign from the organization, and Wallwork begins investigating the planned event. Meanwhile, Fisher reports that the Moscow specialist intends to draw Rutherford out by threatening his mother. Reacher and Fisher arrange another clone handoff intended to protect her cover and make the cell believe its mission has succeeded. Sands creates the copy while Rutherford is disabled by a migraine. At the diner exchange, Fisher warns Reacher silently that the specialist has arrived early, takes the server, and orders Reacher into the Russian team's vehicle.

Fisher covertly asks Reacher to stay with the Russian team. A technician verifies the clone, and Fisher photographs the record the cell wants the FBI to find. Reacher stages an escape that preserves her cover, but comparison with the original archive reveals that the cell substituted an invented third Klitsch brother for Natalia Matusak, the brothers' sister and Henry Klostermann's mother. The forgery points away from Klostermann's family, making his daughter Diane Smith the likely Oak Ridge asset. Fisher's phone activity exposes her, and Reacher and Sands trace the team to the bunker at Klostermann's former spy house. The FBI stops Smith while she tries to flee. Reacher enters the bunker, frees Fisher, and defeats Klostermann and the Russian operatives. Klostermann admits murdering Toni Garza and ordering Marty's death, then dies during the confrontation. John Goodyear arrives and admits working with Klostermann's Brotherhood and helping plan the rally. Confronted with proof of Klostermann's Soviet allegiance and his own suppression of Garza's case, Goodyear remains handcuffed for the FBI and agrees to help against associated groups. Officer Rule withdraws her resignation and seeks his vacant position. Rutherford regains the town's regard, Fisher survives, and Reacher leaves toward Nashville.

The recovered archive reveals that the Russian cell altered a historical record to invent a third Klitsch brother. The original instead names Natalia Matusak, Henry Klostermann's mother, establishing the family line that leads the FBI to his daughter Diane Smith at Oak Ridge. Smith is detained while attempting to flee, but she does not cooperate. Reacher enters the bunker at Klostermann's former spy house, frees undercover Agent Fisher, and defeats Klostermann and the Russian operatives. Fisher survives and Sands takes her for hospital care. Klostermann admits killing Toni Garza and directing the operatives who killed Marty, then dies during the confrontation. John Goodyear arrives afterward and is exposed as Klostermann's Brotherhood ally and the detective who suppressed Garza's case. He remains handcuffed for the FBI and agrees to help identify connected extremist groups. Officer Rule withdraws her resignation and is positioned to seek his post. Rutherford is welcomed back by the town, and he and Sands retain Cerberus and the recovered archive work. Reacher accepts a ride toward Nashville. Speranski and the wider Russian network remain unresolved, as does the planned multi-state Brotherhood rally.