The F+B Ambulance Company is a private ambulance service that is in competition with the Unity Ambulance Company for a city contract. A new law states that the first company to arrive is the one who can pick up the patient. This leads to conflicts between the rival companies. F+B's top driver is Mother (Bill Cosby). Mother keeps a cooler in his ambulance and drinks beer on duty and acts in a brazen manner to everyone, including his boss Mr. Fishbine. Other drivers include the womanizer Murdoch (Larry Hagman) and his partner Walker, the medical student Bliss and his partner Rodeo (Dick Butkus), and Leroy, who is Mother's partner. Jennifer (Raquel Welch) is the switchboard operator who everyone calls Jugs because of her large breasts. She has recently acquired her EMT license, but Fishbine won't allow her to ride with anyone.
After Walker is injured in an accident, Fishbine hires Tony (Harvey Keitel), a former ambulance driver in Vietnam and suspended cop for allegedly selling cocaine. Everyone immediately starts calling him Speed. Speed is partnered with Murdoch, but that ends after one night after Speed prevents Murdoch from raping an unconscious co-ed. That same night, Leroy is killed by a junkie looking for drugs in their ambulance. After a drunken Mother beats up Murdoch for making fun of Leroy, Fishbine pairs Mother with Speed. With another opening, Jugs threatens Fishbine with a sexual discrimination lawsuit unless she is given the job. After Speed fakes an injury to prevent Jugs from facing charges of misusing an ambulance, they two fall in love. Speed then partners with Jugs in an ambulance after Mother admits he'd rather work alone (even though that's illegal).
At a city council meeting, the rival ambulance companies are told neither of them will be awarded the contract. The Unity owner proposes a merger of the two companies, which the city council is for but Fishbine is against. Before an agreement can be worked out, F+B gets an emergency call from their garage. Murdoch, still recovering from his beating, has showed up high and with a gun. All of the drivers from both companies arrive at the F+B garage, along with the police. Murdoch begins shooting at the ambulances, wounding Speed. Mother tries to rescue his ambulance from being shot up, but instead comes face to face with Murdoch. He tries to shoot Mother, but his gun is empty. He is then killed by a policeman.
At the end, the two companies agree to merge and become the F+U Ambulance Company. The charges against Speed are dropped, and he is reinstated to the police force. Even though he is leaving the ambulance company, his relationship with Jugs will continue. Jugs is initially returned to switchboard duty, but Mother insists that she ride with him. As they drive off together, Jugs tells Mother that he needs to start adding wine to his cooler along with his beer.