In North Africa, US Marine sniper Mike Stevens and his spotter Tommy Madison are on a secret mission to assassinate a dangerous terrorist leader attending a Bedouin wedding. Mike botches the assassination attempt, hesitating when the target's son steps in the way. Due to a glare off the sniper scope, Mike and Tommy are discovered by the enemy and attacked. However, a sandstorm forces the enemy to retreat, leaving Mike and Tommy behind. Seeking an immediate evacuation, the two are instructed to find their way to a village where they can be picked up once the sandstorm stops.
However, en route to the village, Tommy steps with a click sound on a land mine which blows off his legs. Moments later, Mike steps with a click sound too, but realizes he has done so and avoids stepping off. Tommy, hoping to prevent Mike from giving him medical attention (and thereby injuring himself), kills himself with his pistol.
Now alone, Mike contacts his superior via transmitter, who tells him that he will have to hold out for a few days before he can be rescued. Exposed to the harsh environment of the desert, he battles both the psychological and physical tolls of the treacherous situation he is trapped in, recalling memories or imagining appearances of Tommy, his girlfriend, his parents, and moments from when he was a young boy.
Mike is visited several times by a Berber, who long ago lost one of his legs as well as his only daughter to a land mine he had intended to take and sell to enemy soldiers. The Berber, who speaks some English, urges Mike to step off and move forward with life. He insists that Mike is a lucky man, after surviving a night attack by desert dogs while simultaneously managing to keep his foot still on the same place.
Mike is later attacked by enemy insurgents, who had traced him to his current location, but is able to fight them off. Mike then reluctantly decides to accept the Berber's advice, having grown weary of his predicament. He steps off, only for the underfoot not to explode. He digs and discovers that what he had assumed to be an explosive was actually just a tin can with a little toy soldier inside of it. He sets off a flare and is finally rescued. Back in the United States, he reunites with his girlfriend, to whom he finally proposes.
