It is the Spring of 1984 in a middle-class New Jersey suburb. Opening up to some very bad 80's pop-rock playing on a clock radio, fifteen year old Jake Livingston is looking outside of his bedroom window and sees a lighted up Chevy Blazer pulling up in his driveway with his mother giving the man driving it a kiss goodnight. He does not recognize the man or the vehicle.
The next morning, we get a brief glimpse into the everyday life of these boys. Jake's younger 11 year old brother Brian is playing a Merlin electronic device having stole the batteries out of his Walkman, a nostalgic reminder this was the mid-1980's before hand-held technology was any more advanced. Jake and Brian are a little surly and typical preteen/teen boys, but generally good kids.
Jake is walking to class with his buddies (one of whom is Robert Downey, Jr.) and his girlfriend Lisa (future superstar Sarah Jessica Parker). We are introduced to Jake's history teacher Mr. Rader, a miserable smart-ass of a man that enjoys teasing his students about the unfairness of life and playing games with them. He gives the students a quiz and tells them plain out he tricked them. Jake is also on the lacrosse team and having practice.
More of the everyday life of the Livingston family with Jake and his buddies coming over to raid the refrigerator and picking on the younger boys. His mother Wendy arrives home to take Jake to get his learners permit. The Livingston's arrive home and Lisa greets Jake. He and Lisa are later in the bedroom doing their homework and when Wendy knocks on his bedroom door calling them for dinner, Jake teases her that they need to put their clothes on first. He opens the door with Wendy's ear pressed to it. She makes them all dinner and tells the kids she's going out for the night.
The boys' father Alan comes over to take them out to a nice dinner before he goes to Montreal. Wendy was going to go out with them as well, but Alan's girlfriend Joanne is in town as well. Alan is a successful lawyer, but a kind man to his boys. The boys generally discuss with Alan and Joanne their times at school. Alan announces he and Joanne are getting married. The boys congratulate him, but seem saddened as well. They arrive home that night to find Wendy even sadder.
Jake and Lisa are at the yard of a house under construction having a bottle of wine she stole from her parents cellar. They enjoy the afternoon together making out
Some school morning later, Jake and Brian hear a coughing in the bedroom from a man they don't recognize. He comes into the kitchen half asleep, red-eyed, and disheveled appearance and awkwardly introduces himself as Sam. The boys are uncomfortable with his presence, but generally courteous.
Jake and his lacrosse teammates are being given an instruction in basic hygiene by their coach, due to the possibility of athlete's foot, telling them after they get out of the shower to first dry their head, then their crotch, then their feet. The coach explains to them one time he had a bad case of athlete's foot and by drying his feet first, then his crotch, he got a bad infection from it, losing a testicle.
Wendy and her neighbor are in the backyard doing work with Wendy telling her about this guy she's with and that they are totally comfortable with each other, but her neighbor warns her that just because she's on the rebound she should not rush into it. Jake overhears the conversation.
Jake and Sam are in the living room gradually warming up to each other with Sam telling him the other morning was not the best way to meet. Sam mentions to Jake he works for a security system company, but wants to have his own business the way others are always trying to rip you off. Sam and Wendy go out on a date for the night.
Jake and Brian are playing near a stream and Brian accidentally kills a bird with his slingshot. They arrive back to their home with Sam visiting. He gets Jake a used dirtbike with his mother having paid for it. Sam is preparing a barbecue for the family and tells the boys how he wants to open his own restaurant. Jake is beginning to suspect this man is all talk and a phony because just a few days ago his recent interest was to open his own security company.
Jake goes into Brian's bedroom declaring Sam's an asshole. Brian thinks he's okay, but like many intelligent kids, Jake has that built in radar and sense of discernment and can't explain why, he just knows the man is up to no good.
Jake and Lisa are at the shopping mall with Jake venting his frustrations to her that the man tries too hard, but Lisa thinks he's being unfair, judgmental and not giving him a chance. But Jake still trusts his instincts.
Jake comes home with Sam installing a security system for the house. His mother is preparing a cake. She announces to the boys that Sam is moving with them. Wendy justifies it that she is desperate for companionship, but Sam had to move out of his apartment and probably out of a job. The boys are totally displeased.
Jake comes home and Brian has a note that his mother has to sign because he got into a fight. Jake agrees to forge her signature for him, providing Brian's assurance he will never get in another fight.
The family is eating at a crowded restaurant that night. Sam is eating an overcooked steak and totally displeased with the food and service. He declares he and Wendy could open a much better restaurant serving mesquite grilled meats and fish if he could buy a piece of real estate and sell it to put up the money for a restaurant. But Jake debunks his idea infuriating Sam. That night they get home, Sam gives Jake a shove and tells him to get off his back.
Jake and his buddies are coming over to his house once again after school only to find Sam laying on the couch half-asleep and watching TV. He tells his friends they need to leave so they don't see Sam. That night Jake is in his room doing his homework, but Sam is blasting loud music and Jake unable to concentrate.
At school back in Mr. Rader's class, a student is giving a report on the fictional Rocky Balboa. The teacher tells the boy the assignment was about real people that were major contributors of the 20th century. He teases the boy asking him if he believes in the tooth fairy too and that Superman can beat up Rocky. Jake calls the teacher an asshole under his breath, but his teacher hears it and tells Jake to say it to his face and not be a coward. Jake denies it. Mr. Rader assures Jake that his grades are not good enough to get on his bad side and to watch himself.
Jake comes home that afternoon with Sam playing pinball and Jake's records. And Brian had a fight with his mother, locking himself in his room.
Jake and Brian get up the next morning to find a note written on a paper towel and $40 in cash that Wendy and Sam have gone to Lake George and be home in a few days. After Brian leaves, Jake goes into his mother's messy bedroom hoping to uncover the truth. There is an almost empty wine bottle and glass on the nightstand. He goes into a jewelry box to find a bag of marijuana and bottle of pills, possibly Quaaludes. He also goes into a duffel bag and finds a hash pipe, another bottle of pills, and small amount of cocaine. Then he finds an area with a tool box and carpet ripped on the side. He opens the carpet and cut floorboard to find an open area lined with silver padding, with nothing inside of it.
A day or two later, Jake comes home from school through the back door as usual and bumps into a sinister man in the house telling him he's waiting for Sam and that he went out to get some beers. Jake asks the man if he's a friend of Sam's and the man sneers back asking Jake if he is. Jake leaves the house.
Wendy and Sam are back with KFC being served for dinner. Sam is watching TV and Jake approaches him in a passive-aggressive way telling Sam he met a friend of his that is an "interesting guy". Jake refuses to elaborate to Sam that remark, but tells Sam the man asked Jake if he was his friend and that he said nothing back. Sam is infuriated at Jake's impudence and tells him to shove it. A fight breaks out and Jake leaves the room.
Jake is in bed that night overhearing a garbled conversation with Sam slapping Wendy calling her a bitch.
Wendy is out in the backyard planting a flower garden the next day and Jake tells her he shouldn't hit her and that what he's doing is not okay, but Wendy says he's really trying. Of course Jake does not fall for this because he already found drugs in her bedroom. Jake tells her he is a deadbeat, loser, and bullshitter.
Jake is in his bedroom lifting a barbell. Sam enters and retrieves the barbell as if it weighs no more than a bag of sugar. He apologizes to Jake for losing his temper and hitting his mother and assures him he's under a lot of pressure, never had a family before, and wants to make the restaurant thing work. Jake sits on the weight bench confidently giving Sam a blank look while he lectures Jake, knowing that this man is all talk because of the drugs he found. Before he leaves, Jake tersely tells Sam to knock next time he wants to come into his room and in return Sam menacingly tells Jake that next time he wants to judge him to not go crying to his mother, but to have the balls to say it to his face.
Wendy and Sam are having a party in their living room with The Band's "The Night They Drove Dixie Down" playing. Jake comes out of his bedroom to see Sam doing a line of cocaine on the pinball machine. Sam sees Jake watching him, but seems indifferent to having been caught.
The next morning, Jake and Brian go into the messy living room to find Wendy and Sam passed out on the couch.
Jake's personal problems at home are escalating and causing him to act out at school. His friends are playing hacky sack during recess and one of them accidentally kicks it into Jake with Jake pushing the kid and almost hitting him.
Jake goes home from school to find his mother in her bedroom a disheveled mess because she has to go to Brian's school to meet with the principal because he got into a fight with another kid. Jake tells her he will go instead. He tells the principal that their mom is sick and he doesn't know what will happen and assures her it won't happen anymore.
Jake and Brian come into the house. Sam screams at Brian how he's hurting his mother. Brian dismisses him and runs to his room saying "eat shit dickface" to Sam, then locking himself in his room. Sam is infuriated and takes off his belt. Jake tries to stop Sam, who pulls him away and about to punch him in the face. Jake tells him to never touch he or his brother again. Sam leaves that night.
Jake comes home from school with his mother sitting at the table doing bills. His father calls up to talk to him and that he wants the boys to visit him in London for the summer. Jake is troubled and probably thinking to himself he won't be alive to see the summer.
Jake and Brian meet at a pizza parlor discussing possible plans to leave. Jake comes back to the house with a candlelight dinner and linguini and cookies his mother made. He declares to her she's a coke addict, but she denies it and he tells her how the whole home is falling apart and that he wants Sam out of the house. She refuses to comply with his wishes.
Feeling more tense than ever and with his problems at home escalated at an all time high, Jake goes into his history class with Mr. Rader giving back the results of their book reports. Jake received an F on his for plagiarism. He has an outburst with the teacher screaming at him for the way he mistreats the kids and competes with them. He storms out of the classroom and letting off steam riding his dirtbike all over the neighborhood. Just as he is approaching his house, he sees Wendy and Sam in the driveway about to leave in the Blazer.
After they leave, Jake goes into the house and discovers a stash of cocaine in the floorboard Jake previously examined. Hoping this will be an opportunity to get rid of Sam, he takes the cocaine and hides it in the chimney of the constructed home he and Lisa made out at.
That night at the house, Wendy and Sam are in good spirits, probably on a drug-fueled high with the four of them having take-out Chinese food. Sam assures them that the differences need to stop, and his plans are coming together. Jake pretends to agree with Sam and assures Brian to do the same. Afterwards a doorbell rings and two creepy looking men enter. A minute later they leave disappointed one of them stating "he never had it". Sam calls Wendy into the bedroom. The two of them are screaming and worried to death. Jake tells Brian to leave the house. Sam comes into Jake's bedroom asking him if he knows what he is looking for. Jake tells Sam he does and to leave the house unless he wants him to call the police. Sam is furious, grabs Jake and tells him his mother put up 10,000 for the drugs and she's as involved as he is. Jake refuses to comply and tell him where the stash is and runs away.
In a popular 80's cliche'd chase scene, a rock soundtrack ensues with Sam in a furious, drug-fueled frenzy relentlessly chasing Jake all over the town, including tearing down a chain link fence and Jake hitting his dirt bike with another car. Then Jake makes it by foot back to his house.
Jake comes into the house and secures all the doors and windows. He's about to call the police, but finds the phone dead. Sam breaks a window to enter the house, grabs Jake, pounds his head on the floor telling him he will hurt his mother if he doesn't comply and tell him where the stash is. Jake agrees.
The two of them go to the house where Jake hid the stash. Jake retrieves it. Back on the way home, Sam is now totally calm, but in a sinister way telling him they need to be family and work together no matter what happens, reassuring him of no pain or gain. Jake is beyond saddened and crushed knowing that he has lost the ability to protect his family and that he and his brother now have to live in this nightmare, but Sam is oblivious to his hurt.
Back at the house, Wendy has finally come to her senses and packed Sam's bags telling him to get out of the house. She tells him she is fed up with his abuse and does not want him around her boys. Sam refuses, she stands her ground, and he slaps her. Jake hits Sam for it and Sam is mercilessly beating Jake up and Brian comes to Sam hitting him on the back with a baseball bat. Sam is about to beat Jake to death with the bat, but in a popular climactic cliché, Jake kicks him in the crotch with Sam falling over. He leaves and the three are a family again.