Adam, a 23-year-old self-employed security technician, is hired by a businesswoman, Alice Comfort, to set up a security system in her flat. After finishing the work, Adam falls asleep on a lawnchair on her roof-garden. When Alice arrives home and finds him there, she impulsively asks him to accompany her to a housewarming party for her boss. He is unsure, but eventually agrees.
After a drive, Alice and Adam arrive at the party. Alice leaves Adam to speak to some people at the party. Adam leaves the house, feeling out of place. Alice later finds Adam outside in the grounds, then leads him into some woods and they have sex.
On the way home from the party, Alice and Adam are caught behind a slow-moving vehicle, which Alice frustratedly overtakes whilst Adam shouts out an obscenity at the driver. Shortly thereafter, Alice is distracted from driving and accidentally hits a stag. She brings the car to a stop, and they drag the stag off the road. While they are moving it, the car that Alice had earlier overtaken pulls up behind Alice's car. Three men get out, badly beat Adam and then rape Alice.
A month passes, during which Adam and Alice physically heal - the only reminder of the attack being an eyepatch that Adam must wear to protect an eye wound he received during the beating - but both remain emotionally wounded. Upon returning to work, Alice receives notification that, while she was hospitalized following her rape, her father died. Alice drives out to his country estate to put his affairs in order, where she discovers a locked chest that she recognizes from her childhood. On the way home, she passes by a group of riders on horseback, one of whom she recognizes as having raped her. She gets his name - Heffer - from one of the other riders.
Alice then contacts Adam, and he makes his way to Alice's father's house where she tells him that she's found one of the men responsible for attacking them. Alice shows Adam the contents of her father's locked chest: a sniper rifle and silencer that her father apparently smuggled home after being discharged from the army. Alice then tells Adam that she intends to avenge herself against Heffer.
Adam and Alice move into Alice's father's home, and spend their days practising shooting with the rifle. After they have become proficient with it, they take a trip out to the edge of Heffer's land and begin plotting the best way to kill him. During their reconnaissance, they learn that Heffer has a dog on his property, which barks whenever they approach the house. Alice shoots the dog, then makes Adam collect its body so that they can dispose of it. A moment later, Heffer comes outside looking for the dog; Alice is preparing to shoot him when a young woman (later identified as Heffer's daughter, Sophie) comes out of the house to help find the dog. Alice and Adam, disturbed by seeing their attacker as a human being, return home.
Over the next several days Alice and Adam try to determine if they should follow through with their plan. Adam, who has been impotent since the attack, steadily becomes more aggressive and committed to the idea of murdering Heffer. Alice, however, has grown reluctant to kill Heffer now that she has seen him in a human context; instead, she sends Adam to clandestinely set up security equipment in Heffer's house in an attempt to determine the identities and locations of his friends who participated in the gang-rape.
Adam succeeds in breaking into Heffer's house, where he learns that Heffer is the submissive party in his relationship with the other attackers. In need of money, they have decided to blackmail Heffer with their knowledge of the rape, forcing him to give them money in exchange for not anonymously tipping off the police as to his identity.
Adam, seeking a means of escape, ends up in Sophie's room; initially, he merely attempts to keep her quiet so that he can get out of the house, but he has a sudden fit of rage and begins raping her. In the middle of the attack, she escapes from his grasp, and Adam returns home, able to maintain an erection for the first time since the attack. He and Alice begin to have sex, but when he starts to become too rough with her she throws him off. Adam leaves the house and heads out into the woods.
The next day, Alice uses a laptop computer that controls the security cameras and watches Heffer in his house. She quickly realises his intention is to kill himself and after grabbing the rifle she drives over, and stops her car just in front of a garage upon hearing a car horn sounding. Alice gets inside the garage and finds Heffer, sitting in his running car, attempting to kill himself with carbon monoxide poisoning. Alice gets Heffer out of the car and into fresh air, saving his life; once he regains consciousness, she helps him back into his house. In the midst of a delirium from the carbon monoxide, Heffer—who doesn't recognize Alice—confesses that, a month ago, his friends voiced their intentions to rape his daughter, but that he convinced them to rape and beat a woman and her friend in the middle of the road instead.
Just then, Alice and Heffer hear Adam calling from outside, and Heffer suddenly turns violent, grabbing her roughly but Alice hits him and frees herself. Adam then bursts into the house, beats Heffer, duct-tapes him to the kitchen table, and holds him down while Alice sodomizes him with the barrel of the rifle that she has fetched from her car; once she is finished, she prepares to kill him, but now feeling pity for him because of the circumstances surrounding the rape, she decides not to pull the trigger. Adam, infuriated, takes out a hunting knife and carves out Heffer's eye. Horrified, Alice runs away; driving back to her father's home, Alice spots Sophie hitch-hiking, and invites her into her car. When Sophie realizes she isn't being taken home, she asks Alice where they're headed; Alice replies, "Somewhere safe."
Back at Heffer's house, Adam taunts Heffer until he hears a car pulling up; as one of the attackers approaches the house, Adam fatally shoots him in the head before pursuing the remaining attacker through the grounds of Heffer's house. Adam shoots him in the leg as he flees, causing him to fall to the ground. Adam then approaches the wounded man and bludgeons him to death with the butt of the rifle. In the final shot of the film, Adam walks away from his final victim and approaches the screen for a close up shot. He effectively breaks the fourth wall by glancing at the audience - leaving the viewer to reflect on the violent act of revenge Adam has committed.Gillian Anderson as Alice Comfort
Danny Dyer as Adam
Anthony Calf as Heffer
Francesca Fowler as Sophie
Ralph Brown as Jamie
Steven Robertson as Bill
Rotten Tomatoes reported that 40% of 20 listed film critics gave the film a positive review, with an average rating of 4.6 out of 10.Ahead of its UK retail release, Straightheads became available on DVD for rental on 24 August 2007. It went on general retail release on 24 September 2007. Dan Reed reported in his blog that himself, Gillian Anderson, and Danny Dyer recorded the commentary in December 2006. The commentary forms part of the special features for the Region 2 DVD which also included deleted scenes with audio commentary (again from Anderson, Dyer, and Reed), behind the scenes cast interviews and the theatrical trailer. Straightheads was re-released on 13 June 2011 with new cover art. It was released to Blu-ray Disc on 22 March 2010 with the same special features as the Region 2 DVD release.
For its U.S. release, Straightheads was retitled Closure and released directly-to-DVD by Sony Pictures. As per the date reported by the website DVD Times, the Region 1 DVD was released on 18 September 2007.