In the midst of a serial abductor/killer's rampage, a beautiful young teen, Riley Lawson (Ashley Johnson), goes missing. When her desperate parents, Will and Kate (Daniel Stern and Illeana Douglas), are contacted by her kidnapper, an insufferable FBI Special Agent (Jere Burns) takes charge of the case. But, from deep within the psychopathic subterranean world created by Otis (Bostin Christopher), Riley turns the tables on her tormentor, manages to escape and to contact her parents. Fed up with the inability of the FBI to find their girl, Will, Kate, and Riley's brother, Reed (Jared Kusnitz) decide to take matters – and justice – into their own hands. But when Otis's brother, Elmo (Kevin Pollack), shows up unexpectedly, the Lawsons find themselves mired in one of the more unusual and macabre consequences of vigilantism. The movie begins with a young teen being held captive in the basement of serial kidnapper/killer Otis Broth (Bostin Christopher) when she receives a phone call inviting her to the "prom." Otis describes to her the tuxedo he has for the occasion and asks her if it makes her "wet." She refuses to play along into his demented game of re-living his High school prom date and he punishes her by turning up the heat lamps suspended over her bed to try and make her comply. She hangs up, then grabs a bottle of lotion and smears it onto the camera lenses he uses to keep surveillance on her from an upstairs room and pretends to use the chains that keep her bound to the room to hang herself. Otis rushes downstairs to stop her, as he approaches the door she uses the loose end of the chain that she broke away from the floor and swings it around, smashing him in the face as he enters. A struggle ensues, and her life ends when she falls back into the bathtub and the lamp falls in, electrocuting her.
After watching her fry to death, Otis yells "No! No! No! Stupid!" then remarks on how frustrated he is that he wasted six weeks holding her captive before setting to work cutting her limbs off with a hacksaw.
It is revealed shortly thereafter that Otis has a job as a pizza delivery man; it is when he delivers to the Lawson household that he sets eyes on Riley (Ashley Johnson) for the first time and immediately becomes infatuated with her, even going as far as to hold the dollar bill she gave him as a tip up to his nose and inhale deeply.
The next morning, while she leaves the house to wait for the bus to school he abducts her in broad daylight, forcing a bag over her head to stifle her screams and throwing her into the back of his hatchback before taking off and driving past right in front of her parents as they leave for work.
The movie progresses as more is revealed about Otis' mentality and his psychotic fantasy to abduct beautiful teenage girls to hold hostage to re-enact his High school prom. He insists on calling Riley "Kim," the girl that ditched him on prom night and ultimately married his brother. Riley wakes up in Otis's basement dressed in an old cheerleader uniform and is forced to act out one of his many scenarios, much to her horror & humiliation. She quickly learns that by resisting him and denying him of re-living the experience causes him to hurt her; however by playing along with his recreated scenarios she eventually finds the chance to escape after the scenario of prom night. When Otis' brother Elmo (Kevin Pollack) comes over for his customary surprise visits to criticize Otis' house and scream at him (usually accompanied with a slap across the face,) Otis must put Riley back in her room but forgets to secure her chains to the floor. She uses the wire from inside her bra to short-circuit the electric fence that seals off the air duct, then crawls through it to the outside and to a local convenience store to call her mother Kate (Illeana Douglas) and tell her everything about her captor and where to find her.
It is then that Kate makes her daughter promise to repeat to NO ONE the address of her captor, or his name. She then tells her husband Will (Daniel Stern) and son Reed (Jared Kusnitz) and they plot to take their own revenge and not include dimwit and perverted FBI detective Agent Hotchkiss (Jere Burns) who had been bungling the case all along out of the picture.
After visiting Riley at the hospital, the trio break into the house at the address Riley told them and wait for Otis to come home, armed with a shovel, a baseball bat and a large kitchen knife. But what Riley didn't tell them was Otis' physical description, so when his brother Elmo popped in for his regular home intrusions to deliver groceries and insults he was greeted by the three attackers in a hilarious effort to attack and incapacitate him.
The scene cuts back in with Elmo unconscious and bound to a chair while the three Lawsons hover around him, thinking of different ways to torture and mutilate him. Father Will runs a wire from inside his rectum to an electrical socket, electrocuting him within inches of his life. Mother Kate holds a mason jar containing chemicals that jolted him awake when it was held to his face and breathed in. Brother Reed cracks him across the face with a 5-iron then shoves a smoking hot curling iron down his throat while Kate prepares to chop off his fingers and toes to put in a blender and then force him to drink.
Little do they know that the same cameras that Otis used to keep surveillance on his victims are still active, although they are not pointed at where Elmo is being tortured they still record all the of the audio occurring. So when Riley finally cracks to Agent Hotchkiss' constant questions of what she knows of her abductor, he contacts the father's cell phone and gives them Otis' description.
Realizing their captive (now dead) was NOT the 6'3", 350 lb. man described to them, they checked his wallet for an I.D. to realize what Elmo had tried to tell them all along - they had the wrong Broth. They then scramble to clean up the mess they made and cut up his body to put into separate garbage bags, which they then load up into Will's pickup truck and ditch in a local dumpster.
Otis comes home to find his house a mess, and that Riley's gone. He then reviews his cameras to hear the family torturing and killing his brother and loses it. Meanwhile Agent Hotchkiss greets the family at the hospital where they are about to bring Riley home from after being released and asks them to meet with him in the hospital's chapel. It is here that he reveals to them the cameras they confiscated from the house (the movie never shows it, but it is presumed the descent of FBI agents was delayed until long after Otis discovered what had happened and left) and tells the family he will not let it get out, that he was glad they got their revenge (thinking they killed Otis and not Elmo) and leaves them to their business. It is when they all return home that Riley tells her family that the man that abducted her was the same man that delivers the pizza, while her mother and father debate on whether to hunt him down again or to move and not let Otis seek his revenge, Reed grabs a shotgun and calls the pizza place to order for a delivery. When the family hears a knock at the door, he asks who it is. When he hears the response of "pizza delivery" he fires four rounds through the door, then opens it to reveal a dead body with the face obliterated by the shotgun blasts lying on the front walkway. Kate asks, "Is it him?"
An Alternate ending on the films Bonus Features is called "The Birthday Party." In it, Otis has tied up the Lawson family and is celebrating his birthday with them. He has made a script, complete with Will blowing on a party noise maker and a birthday song written by Otis. He then opens gifts "given" to him by the Lawsons (a curling iron from Will, a blender from Kate, a golf club from Reed, and a "birthday fuck" from Riley) He then forces Kate to eat from his Birthday Cake. Otis thanks them, calling it the "Best Birthday Ever", and blows out the candle. Sent from my BlackBerry® wireless handheld