Vietnam veteran Bill Schmidt has returned from the conflict and just wants to take it easy for a while. Bill's father-in-law Harry has always disliked him and objects to his plan. So when two other veterans come around looking to cause trouble for Bill, Harry directs them to his house. What Harry does not know is that Bill prosecuted the two men for murder and rape in Vietnam, and they have just been released from prison and want to settle the score with him.

In rural New England, factory worker Bill Schmidt lives with his girlfriend Martha Wayne and their infant son Hal. The couple rent their house from Martha's father Harry, a writer of pulp westerns, who lives and works nearby in a small cottage. Although Bill constantly scans newspaper ads for new housing, Martha scoffs at him, insisting that they have an ideal arrangement. One winter morning, after Bill goes out to retrieve a paper as usual, Martha takes Harry a stack of pancakes which he later feeds to his bull terrier, Mack. Soon after Bill departs, Tony Rodriguez and Mike Nickerson drive up and introduce themselves to Martha as army buddies who served with Bill in Vietnam. When Bill returns minutes later, he greets the pair without enthusiasm while Martha introduces them to baby Hal. Tony and Mike both comment about Bill's expansive house, but he hastily explains that the house and extensive acreage belong to Harry. Over snacks, Tony asks Bill about his life and he and Mike laugh when Bill reveals he works for a company that manufactures helicopters for the military. Later, when Mike asks to lie down and take a brief nap, Bill takes Tony out to look at the property. After delightedly helping Bill feed the family chickens, Tony abruptly grows critical of Bill's comfortable lifestyle. He then reveals that he and Mike have just been released from the military prison at Fort Leavenworth after serving two years for a crime in which Bill testified against them. When Bill cautiously asks for details about their release, Tony affably explains that their lawyers had their confessions thrown out as he and Mike had not been properly advised of their rights. Noting Bill's apprehension, Tony explains he only wanted to offer Bill his forgiveness for his testimony. At the house, Hal's crying awakens Mike who joins Martha. While chatting with Mike, Martha confides that Bill has never told her about his experience in Vietnam, only that he was involved in a court-martial. Meanwhile, Harry grows curious when he sees Bill walking with a stranger and telephones Martha for explanations. Enthused to learn the men are veterans, he invites them to his cottage where he offers them alcohol and regales them with tales about his days serving in the Pacific during World War II. When Bill attempts to comment about the war, Harry scornfully belittles his pacifistic stance. Hearing whining at the door, Harry discovers Mack seriously injured and bleeding. As Bill tends to the dog's wounds, he observes that Mack has been in a fight. At a window overlooking the Wayne property, Tony points to a large black dog loping in the distance. When Harry curses and relates that the neighbor's dog is an area nuisance, Mike goes out to the car to retrieve a rifle from the trunk. Spotting him, Martha grows alarmed and after placing Hal in his crib rushes to her father's house just as Harry and Tony approvingly watch Mike shoot the black dog. While the three men go out to retrieve the carcass which they then carry across the snow to the neighbor, a disgusted Bill and Martha return to their house. Bill then divulges his part in the court-martial of Mike, Tony and two other members of their squad. Bill relates that Mike led a patrol to seek out the enemy Viet Cong in a small village, but, unable to uncover any traitors, he angrily took a teenage girl hostage then later raped her and encouraged the other patrol members to do the same. All but Bill complied and he later turned the others in. Hugging Bill, Martha praises him for his bravery, but he admits his eventual testimony has haunted him ever since. Martha angrily dismisses this and inquires about Mike and Tony's unexpected visit. When Bill says that Tony offered him an apology, Martha suggests Bill ask them to leave, as their presence is disturbing. Meanwhile, Harry invites Mike and Tony to his cottage, then telephones Martha to ask if they can come over to watch a televised football game on Bill's set. Annoyed when Bill falteringly agrees, Martha goes outside for a long walk. As Harry continues to drink heavily during the game, he first admonishes Bill to acknowledge that Vietnam is crucial in the ongoing battle against Communism, then makes racist comments that incense Tony. When Mike joins Harry on the sofa, an uncomfortable Bill goes upstairs to sit with Hal. Bored, Tony strolls about restlessly, while Mike observes that Martha is attractive and questions Harry why she and Bill are not married. Harry scornfully criticizes Bill as weak. After the game ends, Bill listens from upstairs as Harry invites the men to dinner and suggests that they can join a neighborhood coon hunt later that night. Martha returns from her walk, angered to discover that Bill has not asked Mike and Tony to leave. Taking Mike aside, Harry asks him if he knows anything about Bill's involvement with the court-martial. Mike relates the story, and is mildly surprised when Harry sides with his actions and wonders why he did not kill Bill for his betrayal. Martha prepares and serves dinner and grows increasingly ill at ease as Harry, now quite drunk, cuts his hand while attempting to carve the roast. After convincing her father to return to his cottage, Martha makes coffee, which annoys Bill, who retreats to the kitchen. After Tony helpfully offers Martha advice on a fussy Hal, she snaps at him and he joins Bill. Accompanying Mike in the living room, Martha confides that she knows about the episode in Vietnam. When Mike responds carelessly, Martha disparages him, but Mike criticizes her for offending her father by remaining unmarried. Insisting that he has no need to justify actions the army has accepted, Mike maintains that he is a better soldier than Bill. Growing sympathetic to Mike when he reveals he was shocked to see soldier friends maimed or violently killed, Martha hesitatingly agrees to dance with him to radio music. Curious at the lengthening silence, Tony goes to the living room, followed by Bill who is so outraged by Mike's smug look as Martha clings to him, that he attacks Mike. While Tony holds Martha inside, Mike and Bill go outside and Mike beats Bill severely. Returning to the house, Mike and Tony chase the terrified Martha upstairs where Mike violently rapes her. Tony drags the semiconscious Bill back inside, then joins Mike outside where they drive away. Martha drags herself downstairs and sits silently across from Bill.