In Chicago, Illinois, undercover police detectives Danny Costanzo and Ray Hughes spot two criminals, Julio Gonzales and “Snake,” getting out of a parked Mercedes-Benz. Gonzales recognizes the officers, jumps back in the car, and drives off, leaving Snake holding an attaché case. Snake runs down the alley to his third floor apartment, as the officers chase him. They persuade Snake to invite them inside, but he refuses to hand over the briefcase. When he asks if they have a search warrant, the policemen warn him that he will be uncomfortably detained for as long as it takes them to do the paperwork. Reluctantly, Snake surrenders the attaché case, which is filled with $50,000 in cash. Ray asks if Snake has resumed dealing drugs, but he denies the accusation. When Danny searches the apartment, nothing turns up, and the officers cannot make an arrest. Danny goes out on Snake’s balcony, and announces to nearby basketball players that Snake’s apartment has poor locks, and $50,000 for the taking. Snake realizes he cannot protect his windfall, and punches Ray in the face. Danny and Ray arrest him for assaulting an officer. As they drive Snake to the police station, they discover that the money belongs to Julio Gonzales. They stop at a cemetery so Danny can attend his Aunt Rose’s funeral, and he briefly says hello to his former wife Anna. Later, at the station, Anna appears and tells Danny she is getting remarried to a dentist. As they talk, a lawyer delivers an envelope with a $40,000 inheritance check from Aunt Rose’s estate. With the money, Danny imagines he and Ray will treat themselves to fancy dinners and better seats at Chicago Cubs baseball games. Soon, Captain Logan informs them that the unidentified man who jumped from a building the other day was actually a South Side police officer, Alan Jackson. He also mentions that Jackson drowned before his body was pushed off the structure, and orders the partners to investigate the crime. At first, Danny and Ray suggest that Snake lead them to Gonzales, but he refuses. However, when he collects his briefcase and money upon being released, Danny and Ray have withheld all but $5,000 of his cash. He can sue the police department, which will take months, so he is forced to cooperate. The partners outfit Snake with an electronic “wire,” and watch him take possession of a corrugated box that is filled with Uzi machine guns. They follow him to a shipping vessel as he meets Gonzales. The partners expect to carry out an arrest, but are surrounded and captured by Gonzales’s men. However, Gonzales believes Snake has betrayed him and has him killed. Suddenly, two of Gonzales’s men, Frank and Tony, announce they are policemen. A gunfight ensues, but Gonzales escapes with a machine gun. As Frank and Tony give chase, they are angry that Danny and Ray have ruined months of undercover work. Gonzales eludes the undercover officers, but Danny and Ray find and arrest him. Later, the captain criticizes the partners for ruining an undercover investigation, and claims they needed to be rescued like a couple of rookies. He orders them to take vacation. Danny and Ray seek out the sunshine of Key West, Florida, where they meet some women, fish, roller skate, and watch the sunset. Danny convinces Ray to quit the force and open a bar. When they return to Chicago, they give the captain thirty days notice of their retirement. However, Capt. Logan announces that Gonzales is back on the street thanks to his lawyer. The partners are eager to apprehend Gonzales and return to work. They get a tip that he may be living with his girl friend at the El Camino apartments. As Ray and Danny drive to the location, they recognize Gonzales’s Mercedes. Ray takes a can of red spray paint and creates a no-parking zone around the car, and it is towed. Soon, they have a standoff with four of Gonzales’s men. After getting the upper hand, Danny and Ray search the apartment, but Gonzales escapes out the back door. A few floors down, Gonzales grabs a female neighbor, and uses her as a human shield. Gonzales escapes and drives off in their police car. Backup units transport the stranded partners to the station. Capt. Logan warns that the anticipation of retirement is turning them cautious, and caution will likely get them killed. He insists they work together with Frank and Tony to capture Gonzales. A police mechanic transforms Ray and Danny’s abandoned cruiser into a yellow taxicab with bulletproof windows. Soon, the four officers are embroiled in a messy stakeout. Tony accidentally shoots Danny but his bulletproof vest saves him. Afterward, Frank and Tony gloat that they have captured one crook, Juan Martinez, while Ray and Danny have none. Danny recognizes Juan, and pulls him aside for further questioning. When Juan gives them an important tip involving Gonzales’s upcoming shipment of drugs, they remove his handcuffs. They warn Tony and Frank that Juan is escaping. Meanwhile, the partners go to the airport, hoping to ambush Gonzales, but other officers are already on the scene with drug-sniffing dogs. A dog locates a packet of cocaine believed to be worth $3 million, and Frank and Tony get credit for capturing a suspect. Ray and Danny are irked that the captain is treating them as though their retirement is already in effect. As they leave the runway, a drug agent tells them that further tests reveal the drugs found are of inferior grade, and are likely a decoy. At customs, Gonzales meets with a Colombian priest and nun. When he sees Danny and Ray, he escapes in a limousine, leaving the nun and priest behind. Ray and Danny give the priest and nun a ride, and a chase ensues. Gonzales’s limousine drives onto the elevated railroad tracks and the police taxicab barely misses crashing into an oncoming train. The chase continues until Gonzales’s limousine stops for another oncoming train. Gonzales jumps out and disappears into the station just as the train upends his limousine. Back at the station, the partners apologize, saying they mistook the priest and nun to be cocaine smugglers for Gonzales. They cannot find drugs inside the ceramic souvenirs in their suitcases, and the nun and priest are released. Ray and Danny soon realize that the ceramic containers themselves are made of pressed cocaine, and tell the captain. Later, the partners harass Juan Martinez to get new information about Gonzales’s whereabouts. On their stakeout, Gonzales arranges for a trash compactor truck to destroy their taxicab with them in it after they refuse to return the drugs in exchange for a bribe that would cover a mortgage for their Key West bar. The partners escape through the back window, only to discover that Gonzales is gone. The next day, they retrieve Gonzales’s Mercedes from the impound yard, and drive around town looking for him. Anna appears at Danny’s apartment to give him an insurance policy she found, and they fight about his inability to act like an adult. Gonzales kidnaps Anna after she leaves the apartment. He warns Danny that he will kill her unless the drugs are returned. Danny and Ray go to the station, where Ray uses a fake requisition form to take the cocaine from the evidence room. Frank and Tony arrive, sensing something is brewing, but Danny and Ray refuse to give them information. As Danny enters the Illinois State Building, Ray sneaks into the basement. He meets Juan Martinez impersonating a security guard. Juan leads Ray to a cage in which all the real guards have been locked up. Ray discovers the only way up is by the window-washing rig. Meanwhile, as Danny rides up in a glass elevator, Anna passes, descending in a second elevator. Danny opens a duffle bag and displays plastic bags of cocaine. Gonzales gives the signal for Anna’s elevator to rise until it is level with Danny. Suddenly, Gonzales’s associate opens fire on both elevators. Danny orders his wife to drop to the floor. He shoots the associate dead. Ray rappels inside the building’s atrium with ropes. He sees Frank and Tony enter the lobby and orders them to get Gonzales. Danny’s elevator door opens but Anna’s remains shut. He orders her to climb out the top and jump over to his elevator but she is afraid to move. He throws bags of cocaine in the air, and Gonzales is frantic as they burst on the lobby floor. Danny catches Anna and they escape. Ray shoots his way past Gonzales’s men and swings onto firm ground. The partners fire away at Gonzales and he goes down. Ray and Danny argue over who fired the fatal shot, but Gonzales pops up again. After another round of shooting, Gonzales collapses dead on a down escalator, and his bloody body lands on the lobby floor. Anna hugs Danny and smothers him with kisses. Danny and Ray agree that the people of Chicago deserve good protection and Frank and Tony could use more seasoning. At this, Danny turns to the rookies and asks if anyone wants to buy his bar.