A recently widowed single father, Jim Grant (Stanley Tucci), is a former militant of the Weather Underground, wanted for a bank robbery in Michigan back in 1980 and for the murder of the bank's security guard. He has successfully evaded the FBI for over three decades, establishing a new life as a defense attorney in Albany, New York. However, when Sharon Solarz, another ex-member of the Weather Underground, is arrested on October 3, 2011, an ambitious and aspiring journalist named Ben Shepard (Shia LaBeouf) sees this as a golden opportunity to break a national story. His demanding editor, Ray Fuller (Chris Cooper), assigns him the task of pursuing leads.
Ben, aided by his ex-girlfriend Diana (Susan Sarandon), who works as an FBI agent, digs deeper into the involvement of Jim. She hints at the importance of an individual named Billy Cusimano, an aging hippie with a dubious past who operates an organic grocery store and is known to be an old friend of Sharon Solarz. Billy is disheartened when Jim refuses to take on Sharon's case but eventually shares this with Ben during an interview.
As Ben persistently investigates, he tries to confront Jim, but Jim remains tight-lipped. Alarmed by the escalating investigation, Jim decides to take his 11-year-old daughter Isabel on a spontaneous "little trip," initially traveling north to shake off any pursuers. Ben discovers that Mimi Lurie, an accomplice in the infamous bank heist, was recently spotted in Canada, and a private investigator helps him uncover that Jim did not possess a Social Security number before 1979, even obtaining a death certificate under the name Nick Sloan—another former Weatherman. This revelation ignites a media frenzy, drawing increased scrutiny from the FBI.
Meanwhile, Jim and Isabel find themselves in New York City, where they indulge in some sightseeing and check into an upscale hotel. The manhunt for Jim, now under the alias Nick, becomes the talk of the nation. While Isabel naps peacefully, Jim discreetly leaves the hotel room key along with legal documents granting his brother Daniel Sloan (Nick Nolte) guardianship of Isabel. This act doesn't go unnoticed as FBI agents led by Diana's supervisor Cornelius catch their trail, nearly apprehending Jim. However, Jim cleverly orchestrates a diversion, allowing him to slip away unnoticed, while the agents confront Daniel, interrupting his plans to leave with Isabel.
Sharon, assertive in her belief and past, refuses to provide any details to the FBI but does consent to discuss the matter with Ben. She admits to her unyielding views about her radical days in the Weather Underground and reveals a long-forgotten affair between Nick and Mimi. In his quest for answers, Ben interviews Daniel, who becomes irked by the derogatory portrayal Ben writes about him.
In Milwaukee, Jim seeks out his childhood friend Donal (Brendan Gleeson), who runs a lumber yard. Despite initially advising against searching for Mimi, Donal introduces Jim to Jed Lewis, a history professor and former SDS member. Jed shares a contentious view against the violent methods employed by Jim’s former comrades and reluctantly agrees to assist Jim once he learns he has a young daughter. With Jed's connections, they set their sights on tracking down Mimi, who is now involved in marijuana smuggling along the coast of Big Sur, California.
Simultaneously, Ben starts questioning the narrative that Jim is guilty. Ignoring his editor's directive, he travels to Michigan to unearth more information about the bank robbery. During this investigation, he encounters a retired officer, Henry Osborne, who had originally investigated the case. Osborne's reluctance to speak in front of his adopted daughter Rebecca piques Ben’s suspicion that he’s hiding critical insights. Drawing connections between Osborne and Mimi's family, Ben discovers that if Mimi were to testify that Jim was not at the scene of the robbery, he could be exonerated. This leads to a tentative bond forming between Ben and Rebecca.
When Jim finally locates Mimi at a secluded cabin on the Linder-Lurie property, old tensions arise. Though Mimi is unyielding regarding her past, Jim passionately pleads for her to confirm his alibi for Isabel's sake, not wanting their daughter to suffer the same fate they did decades ago when they gave her up. An unforeseen revelation strikes Jim as Mimi discloses that their daughter has grown into a beautiful young woman living in Ann Arbor. Meanwhile, Ben uncovers this hidden truth about Rebecca’s identity and encourages her to reach out to Jim.
Just then, Mimi’s escape plan is set in motion, leading to a tense showdown as she prepares to flee to Canada. When Ben arrives at the cabin and finds Jim, he reveals everything he knows, forcing Jim to make a crucial decision to protect Mimi. Jim opts to leave, drawing the FBI’s attention towards himself, leading to his eventual capture by Cornelius. In a twist, Mimi changes her course and returns to the U.S. to confess her past crimes. Ultimately, Jim is released from imprisonment, reuniting with Isabel, while Ben decides to shield the truth concerning Osborne's actions from coming to light, preserving Rebecca's identity in the process.
