Jacob McCandles (John Wayne) is a big man with a bigger reputation. A successful rancher and landowner, his many businesses keep him conveniently away from his home and estranged wife Martha (Maureen O'Hara). He returns to the ranch after receiving devastating news: a gang of kidnappers has his grandson, Little Jake (Ethan Wayne), and is demanding one million dollars for his safe return. He, his horse and faithful Dog arrive at the ranch where Martha presents him with some of his beloved firearms, a mule and strong box to hold the million dollars while the two hatch a secret strategy to get Little Jake back.The local sheriff has convened a possee complete with then state-of-the-art automobiles. Two of Jake's sons, the passionate, gunslinging James (Patrick Wayne) and the motorcycle-riding, sharpshooting Michael (Christopher Mitchum) elect to go with the sheriff's possee. Big Jake decides to set off across the rough terrain on his horse with his Dog at his side, and soon meets up with his Native American friend, Sam Sharpnose (Bruce Cabot), who has brought additional horses and supplies.The possee quickly runs into an ambush by the gang led by the ruthless John Fain (Richard Boone). The gang escapes, and Little Jake's condition is unknown. The possee's automobiles are disabled, and they have suffered casualties. James and Michael, despite the turbulent past they endured with their father, decide to join he and Sam on horseback to find Little Jake. Big Jake sends Michael ahead of the group to see if he can locate the Fain gang. As the group makes camp that night, they are approached by Fain pretending to be just a messenger boy. He asks where Michael is, and is informed that he was killed in the firefight. As they talk, Sam jumps on two of the gang trying to ambush the camp, and apologizes to Jake for only killing one. Fain informs Big Jake to proceed to the next town where they will be met and given further instructions. Michael returns to the camp with the news that Little Jake is alive.Upon arrival in the town, it's clear that festival preparations are underway. Big Jake and the boys hole up in a hotel room while Sam bunks in the barn (Indians aren't allowed in the hotel). They then devise their strategy: James will go have a good time in the saloon, Big Jake will head to the barbershop for a shower, Sam will secrete himself on the roof of the hotel, seemingly leaving Michael alone protecting the strong box. Big Jake tells Sam to listen for a "disturbance" in the street, and use the distraction to join Michael in the hotel room to protect the strong box.As Big Jake predicted, the gang tries to hit the strong box when it looks most vulnerable. Fain and another of his gang members start a fight with James in the saloon, one keeps a gun on Big Jake in the barbershop, and two others come up the hotel stairs and toward the room. Big Jake dispatches his captor in the barbershop, James fights his way out of the saloon with Jake's help, and the two head to the hotel. At the hotel, once Sam hears the fight in the saloon, he climbs over the roof and slips in the window to aid Michael in protecting the strong box. Shotguns blast as the gang hits the hotel room. When James and Jake arrive they find Sam, Michael and the Dog unharmed, but the strong box has suffered damage. To their horror, James and Michael realize they've been risking their lives to protect a box of newspapaer clippings! When confronted with his deception, Big Jake admits that he and Martha never intended to pay for Little Jake: they intended to take him back all along. James and Michael take out their frustrations on Big Jake, but vow to stick together to save Little Jake.The following evening the gang contacts Big Jake and instructs him to proceed alone to the old churchyard outside of town to exchange the strong box for Little Jake. They caution Big Jake to come alone and not try anything, and inform him they have a sharpshooter on Little Jake just in case anything goes wrong. Big Jake takes the few moments he has to plan with his sons. He tells Michael of the sharpshooter and instructs him to find a high position and take him out whenever he can. Big Jake takes the Dog and goes to the meet as instructed, while the others follow discreetly behind. As he enters the churchyard, he spits tobacco in the eye of the first guard, enabling Michael to quickly clamber up a water tower unnoticed. James hides just outside the churchyard entrance, and Sam goes around the back by the barn, as Jake and the Dog proceed into the courtyard.Fain meets Jake in the courtyard, just outside the barn hayrack. After the Dog attacks one of Fain's men hiding in the shadows, Big Jake asks for all of Fain's gang to back off. Little Jake is brought out, hands bound and hooded, on a horse. After a bit of cat-and-mouse, Little Jake is unmasked and Big Jake hands the key to the strong box over to Fain. As Fain unlocks the strong box, he realizes he's been had. Big Jake whispers to him that no matter what happens, Fain will be the first one to die. Fain screams his command to kill the boy, and throws his lantern on the worthless strong box. Fain's sharpshooter fires a round at Little Jake, but misses. Big Jake pulls the boy off the horse and takes cover behind some hay bales. Michael sees Fain's sharpshooter in the bell tower of the old church, and drops him with his second shot. Sam and the Dog join the fight, with the Dog giving his life protecting Little Jake from one of Fain's machete-weilding gang. Big Jake is wounded, and exchanging shots with Fain's gang. He gives Little Jake his derringer and instructs him to run toward the entrance of the churchyard. Little Jake takes off as Big Jake lays down cover fire. Sam points him toward James at the exit, who helps Little Jake escape. Fain and Big Jake are in a duel to the death, when Michael takes a fatal shot at Fain, saving his father and Little Jake. After a harrowing journey and a risky gamble, the family leaves, happy to be together.