In 1934, after two years on the run as robbers and murderers, the criminals Bonnie and Clyde break several associates out of the Eastham Prison Farm in Texas. In response, Texas Department of Corrections Chief Lee Simmons persuades Governor “Ma” Ferguson to hire former Texas Ranger Frank Hamer to track down the criminals independent of the Bureau of Investigation (FBI). Ferguson and her staff are skeptical, having disbanded the Rangers for more advanced units, but she reluctantly allows Simmons to go ahead. Hamer initially hesitates due to his family, but both he and his wife accept after hearing about a devastating shootout in Missouri involving the infamous pair. Hamer’s former partner, Benjamin Maney Gault, joins Hamer after a long period of being unemployed and living in hardship.
The FBI has been wiretapping the fugitives’ families for a while. Hamer and Gault get access to the files and conclude they are likely making their way “home” to Dallas and drive there; shortly after arriving, they see a man throw a bottle at Bonnie’s mother’s house and then a boy picking it up. Suspicious, they give chase, but the boy escapes. FBI agents arrive, telling them that Clyde is believed to be in Brownsville, hinting in a snide way that the “retired Rangers” should stay out of the operation.
The Rangers brush off the FBI and meet with Dallas Sheriff “Smoot” Schmid, who introduces them to Deputy Sheriff Ted Hinton, a childhood friend of Bonnie and Clyde who can identify them on sight, so Hamer and Gault decide to bring him along, although they are concerned over Hinton’s previous hesitations to fire on the pair, especially Bonnie, who he was sweet on as a child. The next day, they hear of a double police murder committed by Bonnie and Clyde near Grapevine. Investigating the site with Hinton, Hamer is appalled by the pair’s brutality and emphasizes it to Hinton. They also find that Bonnie was accompanied by a white rabbit. Hinton tells them it is likely a present for a family member.
Leaving Hinton behind, Hamer decides to break his jurisdiction and drives to Oklahoma. Getting gas at a gas station, Hamer questions a gas attendant who makes it clear he is sympathetic to the criminals, but Hamer attacks him, and at gunpoint, the attendant says the gang came through and were headed to a migrant camp. Once there, the two learn from a local girl that the gang was there and investigate the criminals’ campsite. Continuing their pursuit, the Rangers hear on the radio of two more murdered police officers about 20 miles away. They make their way to the site, but since they are outside their authority, the FBI and local police bar them passing the roadblock. Frustrated, Hamer unexpectedly drives around the roadblock and continues to Coffeyville, Kansas, believing the Barrow gang will stop there for supplies. Bonnie and Clyde do a drive-by, but as they close in for a shot, adoring crowds surround Bonnie and Clyde’s car, cheering on the criminals and blocking the Rangers. They give chase, catching up outside the town, but Bonnie and Clyde turn off into a dirt field and kick up so much dust that despite briefly exchanging shots, the gang evades the Rangers.
Trying to pick up their trail the next day, Hamer is told that Clyde had breakfast in Amarillo and returned to Dallas to find out the white rabbit had been delivered to Bonnie’s family. The Rangers go to the (business) garage of Henry Barrow, Clyde’s father, where Hamer confronts him, and the father tearfully asks Hamer to “end it” for his family, knowing his son would never be taken alive.
Hamer follows up on a plan by Gault to have Simmons furlough a prisoner, Wade McNabb, associated with the gang, hoping to draw them out. While Hamer interrogates McNabb in a bar, Gault is threatened in the restroom by three thugs sympathetic to the gang, but knocks down one and holds the other two at gunpoint until he leaves. Hearing that Bonnie is due to meet a hairdresser the next day, the Rangers keep watch at Bonnie’s home where they witness a man throwing a bottle at the house and the same boy retrieving it again and give chase. They catch up and find a message in the bottle from the gang that they are heading elsewhere, and suspect McNabb warned the gang. Visiting McNabb’s home for more information, the Rangers discover his corpse, savagely beaten to death with a bat. Gault believes McNabb’s death to be his fault while Hamer tries to dissuade him, leading to an argument. They reconcile and continue. By analyzing their adversaries’ movements and believing that “outlaws always go home,” Hamer and Gault predict they are heading for Louisiana, to the home of gang member Henry Methvin’s father Ivy, who lives in Bienville Parish.
The two go to the house and find evidence that the outlaws were there. Joining forces with the local sheriffs after confirming they are not corrupt, the posse corners Ivy who tells them, in exchange for his son’s safety, that the gang is expected soon and that there is only one road to and from his home. The posse is then joined by Ted Hinton and Dallas Sheriff’s Deputy Bob Alcorn. That night as they wait over a game of cards, Gault tells the posse of his first deployment with Hamer. They attacked a gang of murderous bandits, killing them all, including a 13-year-old boy Gault accidentally shot.
Ivy later arrives and tells them the gang is coming the next day. Setting up an ambush, Hamer orders Ivy to join them and pretend his vehicle has broken down to stop the gang at the ambush point. When Bonnie and Clyde arrive, they stop to assist Ivy as planned. Hamer steps out, ordering them to raise their hands. When they do not comply and prepare to draw their own weapons, the posse guns them down before the duo has any chance of escape.
The bullet-riddled car is towed along with Bonnie and Clyde’s mangled bodies to Arcadia, Louisiana, where it is mobbed by hysterical onlookers. Refusing an offer of $1,000 for an interview from the Associated Press, Hamer and Gault quietly drive home. In the final scene, Hamer pulls over and finally lets Gault drive.