Jeff McDowell and his wife Denise watch an old movie on TV when their young daughter comes down from her room claiming a man is in it and looking at her. Jeff goes up and finds it was just clothes on a chair. To calm Megan, he tells her that monsters can't get to her if she hides under the blankets. When he turns off the light by the door, the scene suddenly changes to the interior of a hut in Vietnam. He turns the light back on and everything's back to normal. He cautiously turns the light off again, and it's still okay. Jeff returns to Denise a little shaken. In Megan's room, a wheelchair approaches the bed. She hides under the blanket, but the man slowly pulls the blanket off.
The next day, Denise takes Megan home after school. Jeff is upset because a student asked him about what he did during Vietnam. Jeff hid the fact that he went to Canada. Denise takes Megan back upstairs to wash her hands before dinner. When she looks in the mirror, she sees a man in the wheelchair and an army jacket. Her cries bring Jeff running, but he tells her he didn't see a man coming down the stairs and a wheelchair could never negotiate them anyway. He goes upstairs, where he sees tracks in the carpet. He's suddenly in a Vietnam river with a fellow soldier, under fire. Jeff freaks out and falls screaming in the river. Denise breaks him out of his spell.
The couple discusses what's happening. Jeff thinks the legless veteran is the man who went to Vietnam when he refused to go. Denise tells him it was an unjust war that he helped to end. He's becalmed, but when he turns around, he's in a club in Vietnam, dancing with a Vietnamese woman among other soldiers. He breaks free of Denise and runs to his car, driving away before she can stop him.
At work, Denise gets a call from Jeff, who calls her "Dennie," his old nickname for her. He asks her to meet him at home. After she leaves, Jeff comes to the office, having spent the night in his car. The secretary tells him she directed a call from him to Denise. Alarmed, Jeff runs from the office. Denise goes up to their bedroom, where the legless man closes the door behind her. As she screams, Jeff enters the house. Grabbing a fireplace poker, he runs to her. He confronts the man but recognizes him as another version of himself. He suspects the man is a dream, but the vet believes he's an alternate version of Jeff. In his life, Denise was killed in a motorcycle accident after he left for Vietnam. Jeff thinks the man is here to take retribution for what happened. But the vet has no intention of hurting the family. He lost everything that ever mattered to him and he's dying. In his VA hospital bed, he wondered and concentrated on what might have happened if he had not gone to Vietnam. With enough concentration, he found himself in Jeff's life. He's happy that Jeff made a good life. Jeff, in turn, considers the man a hero. When the vet says it's time for him to leave, Jeff remembers the flashbacks and wonders if it goes both ways. He offers to give the vet his memories. The vet objects, not wanting to give Jeff all his bad memories, all his years of pain and suffering. Jeff is undeterred. The two men touch hands. The vet sees Jeff's wedding day and his legs grow back in. He says they're both heroes. The men reach to embrace, but the vet is gone in a flash of light. Jeff and Denise hug, grateful for the life they have.