Sam finds himself in the body of a solider in Vietnam, yelling "Tom!" from when he Leaped previously. The other soldiers in Bravo Squad respond to his yellow and open on the Vietcong in the surrounding jungle. Sam ends up in the water and by the time he gets back above the surface, he finds himself face-to-face with... his brother Tom Beckett, who wonders how his fellow soldier, "Magic," knew about the ambush.
Back at the base, Colonel Deke Grimwald is speaking with photojournalist Maggie Dawson. As he tries to impress her with his credentials, she sees a helicopter coming down river towing a soldier on skis. Inside the helicopter, Sam is enjoying being back with his brother and figures that he can save him directly. As the helicopter comes down, the skiing soldier, Blaster, loses his balance and goes underwater. The helicopter lands and Tom and the others get out. When Grimwald wonders about their missing soldier, Tom assures him that he's fine and Blaster comes up from underwater right next to Grimwald. The colonel takes Tom aside and tells him that he'll be taking Maggie out on a special op.
Al arrives as Sam tries to clean his rifle. Trying to find a place to talk to Al privately, Sam says that he's going to take a shower to impress Maggie. The other soldiers all head for the showers, leaving Sam alone with Al. Sam tells him about Tom and has determined that he's Leaped to 24 hours before Tom is shot and killed by the Vietcong. Al warns him that he's not there for that. They've identified Sam's Leapee as signalman second Herbert Williams, who everyone calls "Magic" because he's always spotted ambushes. According to Ziggy, Sam is there to guarantee the success of Operation Lazarus, but the code name is the only information that Ziggy has. Sam wants to save Tom but Al warns that they have to focus on the mission while trying to figure out how Tom dies.
Tom comes in, arguing with Grimwald about taking Maggie on the op. Maggie agrees with Tom but asks if she can stay at the base to take some photos for background. Grimwald agrees and Tom tells Sam to set her up with a bunk in the communications bunker. As Sam leaves with Maggie, Grimwald tells him to send in Titi, a "chieu hoi," a local Vietnamese woman who has defected to the American side. Once they're alone, Grimwald tells Tom that Titi will lead him to Mai Choi, ten klicks up the river, to complete Operation Lazarus.
Later, Sam joins the rest of the squad at the bar. They're drinking and trying to impress Maggie, who is drinking right along with them. Al returns and tells Al that Ziggy has found a story in the files about a sapper attack that night that Maggie reported. Maggie listens in as Sam seemingly talks to himself, while Al briefs his friend on the probability that the attack will kill Grimwald. However, if Sam saves Grimwald, he will Leap, leaving Tom to his death. Despite that, Sam tells the squad that he can "sense" sappers. They accept his word and move out, much to Maggie's surprise.
Tom is meeting with Grimwald and Titi when he hears about Sam's warning. He tells Grimwald to stay put while he and his men set up an ambush for the sapper. He puts Sam on the minigun and they wait for the sappers to arrive. Al walks Sam through prepping the minigun while Tom spots Maggie taking photos. He orders her into the bunker with Titi and tells the chieu hoi to shoot Maggie if she tries to leave. Titi draws a gun and seems quite willing to kill the photojournalist.
The sappers never show, much to Al's surprise. He figures that it was too dark for the sappers to see the ambush and back off. Sam believes that it's a good sign since it shows that he can alter history. Maggie goes to the communications tent and Sam, the radio officer, secures the net. The photojournalist starts undressing and Sam hastily looks away, while Al doesn't. Sam discovers that the frequency has been changed and finally gets Al to tell him the proper frequency. Once he resets it, Maggie pours Sam a drink and explains that someone above Grimwald told her about Operation Lazarus, and she wants in to bolster her reputation. She flirts with Sam, trying to convince Tom that he feels she's lucky and should bring her on the mission. Al figures that Sam won't fall for her seduction and is surprised when Sam does as they end up in bed.
Afterward, Al wonders why his friend slept with a woman and Sam explains that if he alters history so that Maggie files her story, then Ziggy can access the newspaper files. Sam goes to see Tom and convince him, insisting that he has a sense about the future and that Maggie has to be there. Tom comments that "Magic" sounds like Sam, who also got feelings about the future. One of them was that he was in danger the next day and successfully bet him that he'd hide in a hole. However, Tom feels honor bound to carry out the mission, but agrees to take Maggie with them.
The next day, Bravo Squad departs but Al doesn't show up to tell Sam that Ziggy has found the information from Maggie's story. The squad goes over their plan to capture a Vietnamese major, and Tom tells Maggie to stay in the chopper. Tom finally reveals that they're rescuing several American POWs. Al arrives and tells Sam that the POWs don't get rescued, and Maggie never filed her story because she was killed on the mission.
The next day aboard the helicopters, Sam worries that he may kill everyone by tampering with history, but Al assures him that Tom won't stop even if Sam tries to persuade him to quit. Grimwald and the other pilot land the choppers and drop off Bravo Squad and Titi. Maggie is onboard, taking photos, and asks to use the bushes. Grimwald reluctantly agrees and as soon as she's out of sight, Maggie sneaks away.
Bravo Squad spots a team of sappers and kills them. Sam checks their bodies and finds a radio set to the first frequency on the radio for the previous night.
Grimwald realizes that Maggie isn't coming back but has no choice to head for the insertion point.
Titi leads Bravo Squad toward the village and Tom orders Sam and Doc to cover their escape and remain on the trail. Al appears and tells Sam that Operation Lazarus is a rescue mission and the POWs are nearby. He wants Sam to come with him and free them, but Sam has been examining one of the sapper's radios with the base frequency, and realizes that Titi warned them the previous night so that they could avoid the ambush. He figures that she's leading Tom and the others into a trap and insists on going after his brother. Doc assumes that he's gone nuts and tries to give him a sedative, and Sam begs Al to help him.
Maggie unwittingly avoids a booby trap and spots the POWs being moved by the Vietcong. She takes photos of the American soldiers and then quietly breaks into tears at the sight of their beaten features.
Sam convinces Doc to come with him, and has Al scout for trip wires so they can avoid them and make a faster time than Tom and the others. Al checks ahead and confirms that the Vietcong have set up the ambush, and tells Sam to call Grimwald. When the Vietcong prepare to open fire on Tom, Sam and Doc arrive from the rear and kill them. Grimwald fires a missile barrage from the chopper, while Titi prepares to shoot Tom from behind. Sam gets to his brother just in time to shoot Titi and save his brother, and they head for the choppers. They run into Maggie, who inadvertently sets off one of the booby traps. As she lies dying, she looks up and seems to see and recognize Al. The soldiers get her body and take it with them rather than leave her in the jungle, while Sam recovers her camera.
Back at the base, Bravo Squad goes to the base to drink in Maggie's honor. Sam gets drunk, blaming himself, and mutters that Maggie didn't die the first time. Tom doesn't understand what he means and assures him that he didn't get Maggie killed. Al appears as Sam realizes that he traded Maggie's life for Tom's.
Grimwald comes in with the last photos that Maggie takes, and admits that he blames himself for letting herself go on the mission that ultimately got her killed. As Sam takes the photos, Al tells his friend that Maggie won a posthumous Pulitzer Prize for her last photograph... which shows Al as one of the POWs. Sam realizes that saving his brother cost Al his freedom, but his friend assures him that he was repatriated in five years, and that in his mind he was always free.
Tom turns to Sam, realizing that it's midnight and that he survived despite his younger brother's prediction in Indiana. He embraces Sam and, to Sam's surprise, calls him "little brother"... and Sam Leaps.