On a Friday July morning in downtown Los Angeles, a middle aged ex-convict, Lonnie (Ivan Dixon), greets his fellow workers at the Dee-Lux Car Wash, including: Hippo (James Spinks), a large good natured man; Snapper (Clarence Muse), an elderly shoe shiner; Geronimo (Ray Vitte), a thin, African-American with feathers in his hair; Goody (Henry Kingi), a Native American who wears a hat with pig ears; T.C. (Franklyn Ajay), who dons a three piece suit and a large Afro hairstyle; Chuco (Peppe Serna), an Hispanic Casanova; and Scruggs (Jack Kehoe), a cowboy and fuel pump operator. The men change into their orange overalls as Earl (Leonard Jackson), their uptight supervisor, orders them to work when Leon "Mr. 'B" Barrow (Sully Boyer), the owner of the car wash, drives up with his college-aged son, Irwin (Richard Brestoff), who spouts communist philosophy and carries around Mao Zedong's Little Red Book. Marsha (Melanie Mayron), the busty cashier, opens the office. Two of the employees also introduced are Floyd (Darrow Igus) and Lloyd (DeWayne Jessie), they are singing musicians who have an audition for an agent at the end of their shift and spend the entire movie doing their jazz-blues dance moves in front of bewildered customers. Another employees is Charlie (Arthur French), a perpetually sick middle-aged employee.Meanwhile, a prostitute, Marleen (Lauren Jones), sneaks out of a cab to avoid paying the fare and hides in the car wash's ladies room.Earl is furious when worker Duane (Bill Duke) strolls in late. The tall African American refuses to answer why his late for work and also why he didn't show up for work yesterday. Duane tells Earl not to call him anymore by his so-called slave name, "Duane," and insists he be addressed as Abdulla Mohammed Akbar, as he is recent Muslim convert. Lonnie tries to be friendly towards Duane/Abdulla, but the young and angry black Muslim refuses to talk to or confide in Lonnie either about what is bothering him.As the men work, they dance to disco music, but the radio show is interrupted by a news bulletin announcing the threat of a "pop bottle bomber," who fashions soda bottles into bombs and blows up small businesses. Meanwhile, Irwin, who just smoked a marijuana cigarette, informs his father, "Mr. B," that he wants to join his "exploited brothers" washing cars, but Irwin slips, goes through the car wash, and gets a hot wax treatment.When the radio promises concert tickets to the first caller to correctly identify a song, T.C. rushes to the telephone booth, but he does not have a dime to make the call. As he screams in frustration, a Mercedes automobile arrives with a boy vomiting out the window. The mother (Lorraine Gary) tells Chuco to wash the car, as she drags the boy to the ladies' room. She bangs on the locked door until Marleen comes out wearing a new wig. When the woman returns to her spotless Mercedes, she accuses Chuco of shoddy workmanship and withholds her 5¢ tip, but her son vomits all over her and the car's interior as she leaves.Later, Reverend Daddy Rich (Richard Pryor) and the sexy Wilson sisters (The Pointer Sisters) arrive in a gold-painted Cadillac. The workers swarm to hear the Reverend preach the gospel of prosperity. Only Duane/Abdulla refuses to listen to his words despite the Wilson Sisters performing a song in front of him and everyone as Daddy Rich collects donations and leaves in his limo.A little later, when a Doberman Pinscher escapes from a vehicle, Scruggs catches the dog, but not before it excretes in the parking lot, and Earl orders Goody and Chuco to clean up the mess with a discarded donut box. Afterward, Chuco puts on Goody's pig hat, sticks his face against a frosted window and oinks, scaring the cashier Marsha while she is using the ladies' room. When Chuco returns Goody's hat, Marsha mistakenly believes Goody is the culprit and dumps a bucket of cold water over him, but Goody later gets even with Chuco by putting hot chillis in Chuco's sandwich.T. C. takes his lunch break at a café across the street and asks Mona (Tracy Reed), a waitress, for a date. She refuses, claiming she is through with dating men who have no future.Later, "Mr. B" propositions Marsha for sex and she tells him she has to check if she is free.Through most of this, Scruggs talks with his best friend Geronimo about calling Scruggs' wife, Charlene, since Scruggs never came home from work the previous day having spent it with Geronimo at a brothel. The sly and womanizing Geronimo gives Scruggs advice to be patient for Scruggs' wife will welcome him home at the end of the day like any other loyal wife.Meanwhile, Hippo pays Marleen to have sex with him in the storage room.Back on the wash line, Irwin preaches communism to the workers, but Duane cuts the boy off, claiming that when the revolution comes, whites will be working for black men.Lonnie tries to mentor Duane/Abdullah while struggling to raise two young children, who visit the car wash. Lonnie also fends off his parole officer who makes an unannounced visit to check up on him. At the same time, Duane/Abdullah confronts the drag queen employee Lindy (Antonio Fargas) and sharply criticizes his cross-dressing, to which Lindy coolly replies, "I'm more man than you'll ever be and more woman than you'll ever get".Seeing a van parked across the street, Duane leaves to talk to the driver. When Duane returns, Lonnie warns him to stay away from the driver, who is a fellow ex-convict.Employee Justin (Leon Pinkney) clashes with his girlfriend, Loretta (Renn Woods), who wants him to go back to college, but he refuses out of the feeling that a black man like him will not get anywhere in the world with any kind of education. She refuses to get married to him unless he goes back to college.It is also revealed that Snapper is Justin's elderly grandfather and he is a follower of Daddy Rich.As another news report about the "soda pop" bomber is broadcast over the radio, a man (Professor Irwin Corey) fitting the bomber's description drives up, asks Hippo for his soda bottle, and disappears into the men's bathroom. Hippo warns T.C. that the man will blow up the car wash. When the man comes out of the bathroom, T. C. grabs the bottle and runs away screaming. Another customer tackles T.C. and the bottle smashes onto the concrete, revealing a urine sample for the man's liver test.Meanwhile, a handsome man arrives and asks Marsha for a date. She agrees, then tells "Mr. B" she cannot meet him later because she has to visit her sister.Sly (Garrett Morris), a con artist employee and bookie, gets arrested by the police at the car wash for a series of unpaid parking tickets.At the end if the day, "Mr. B" fires Duane over his unexplained absences from work for the past several weeks, and Duane angrily confronts and physically threatens Mr. B. However, Lonnie prevents his friend from assaulting their boss, who storms away. When Lonnie asks "Mr. B" to rehire Duane, and also for a raise, "Mr. B" claims he has no time to talk and Lonnie storms away in frustration. Later, "Mr. B" follows Lonnie to the locker room, promising to continue their conversation the next day.When Scrugg's wife shows up at the car wash, she instead throws him a suitcase containing all his clothes, thus throwing him out of their house for staying out all night and cheating on her. Geronimo makes a hasty retreat, and Scruggs ends his friendship with Geronimo for giving him bad marriage advice.As the car wash closes for the day, T.C. telephones the radio station and finally wins tickets for the concert. After T.C. changes back to his suit, he goes to the diner and asks Mona to accompany him. She agrees to go to the concert.As Justin and his grandfather Snapper wait for the bus to pick them up, Loretta arrives in her car to drive home with Justin, and he agrees to talk about his career choices next week.Earl leaves to discover the donut box of dog excrement on his car, while Geronimo and Goody drive away with Goody yelling "you clean it up!"Scruggs leaves the car wash alone with his suitcase to spend the night someplace else.Lonnie volunteers to close the office so Marsha can keep her date. As he counts the cash, Duane enters with a revolver, demanding the money, but Lonnie refuses, explaining that he will not allow Duane to go to prison for such a small sum. Duane is unable to shoot Lonnie and cries that he is unable to deal with life's pressures. Lonnie embraces his friend and says they will figure out a solution together.In the final shot, Marleen watches the men leave as she waits for her next customer.