Smooth-talking, African-American disc jockey Frankie J. Parker attends a karate class at the Los Angeles community center run by his longtime friend, Charles Atkins. Charles urges Frankie to use his influence to raise funds for the much-needed center, but the narcissistic Frankie is concerned about antagonizing his white boss. During Frankie’s radio show, however, he relents and asks his listeners to send contributions to his post office box. His announcement is heard by Melinda Lewis, who has just arrived from Chicago, as she drives her rental car. That night, Frankie goes to the nightclub owned by a friend, former football player Tank Robertson, and there meets Melinda. Although Melinda dislikes Frankie’s womanizing patter, she accompanies him to a party on Tank’s yacht. While Melinda mingles, Frankie is confronted by his former lover, Terry Davis, who is jealous of Melinda. Frankie dismisses Terry, then takes Melinda to his apartment, unaware that they are being followed by a large thug. Melinda allows Frankie to seduce her and the couple spends the next day exploring Los Angeles. At dinner, Melinda tells Frankie that he is more than just his “jive talk,” and that he should think of himself as “heavy and deep,” because there are already too many hustlers in the world. Moved by Melinda’s sincerity, Frankie admits that he has feelings for her. The next day, Frankie rushes home from work, but when he arrives, he discovers that the apartment has been ransacked and that Melinda has been brutally murdered. The thug who had been following them, Melinda’s killer, calls the police, who suspect that Frankie is the culprit, especially after they find Melinda’s driver’s license and learn that, unknown to Frankie, her name is Audrey Miller. Frankie is beaten and interrogated until he is freed by a lawyer sent by Tank, after which he goes to Tank’s house. Terry is waiting for him there and, quelling her hostility, she tries to help him determine why someone would kill Melinda. Soon after, Frankie traces Melinda’s steps by finding her rental car. As he is leaving the rental agency, however, he is stopped by a white junkie named Marcia who pretends to have car trouble and begs him for a ride. Once in Frankie’s car, Marcia pulls a gun on him, but Frankie maneuvers the vehicle in order to get the weapon. He then takes her to Tank’s beach house and questions her until she reveals that a black man named Smith offered to give her drugs if she brought Frankie to him, and that Melinda had something that Smith wants, although Marcia does not know what it is. At the address given to him by Marcia, Frankie finds a white drug dealer who also does not know Smith’s identity, merely that he works for the Chicago gangsters searching for Melinda. After knocking the man unconscious, Frankie returns to the beach house and there discovers that Marcia has been killed. Frankie then finds a place to hide with Terry, but when he goes out for air, he is chased by a car and attacked by two men. After defeating one man with karate, Frankie beats the other man, who he ascertains is Smith. Smith reveals that Tank is in league with the gangsters who killed Melinda, and the enraged Frankie takes the wounded man to Tank’s nightclub. Pelting Tank with karate kicks, Frankie forces him to admit that he is partners with white Chicago mobster Mitch, but Tank swears that he was not involved with the murders. Tank reveals that Melinda was Mitch’s mistress and that when she left him, she took something that Mitch desperately wants. Meanwhile, Mitch, who has come to Los Angeles, upbraids his right-hand man, Gregg Van, for allowing his thug to kill Melinda and for not retrieving the item. Gregg has discovered that she had placed the object in a safe-deposit box, but when Mitch attempts to gain access to the box, the bank manager thwarts him. Meanwhile, Frankie has his secretary check his post office box and discovers that Melinda mailed her safe-deposit box key to him. Mitch summons Tank, who protests that he no longer wishes to be involved, even though he still owes Mitch money. Mitch convinces him that unless he can make Frankie cooperate, however, he will “turn Gregg loose” on Frankie. At Terry’s office, Frankie shows her the key, then laments the impossibility of finding out what is in the box. Terry persuades him to give her Melinda’s driver’s license, then, posing as the dead woman, goes to the bank. A suspicious clerk summons the manager, and it is only when Terry loudly accuses him of being racist that he ushers her into the vault. Terry retrieves the item and runs to the waiting Frankie, who is mystified to discover that it is Melinda’s gold cigarette case, shaped like a miniature safe, which was given to her by Mitch. Determined to unravel the mystery, Frankie orders Tank to demand a meeting with Mitch on his own territory. Mitch stalls for an hour, during which Gregg kidnaps Terry, and Mitch remembers how the problem began: Hoping to expand his influence, Mitch agrees to assassinate a black labor leader running for president of an important union, and at a meeting after the murder, shows his employers motion picture footage of the assassination. Unknown to Mitch, Melinda has hidden a tape recorder in the room to get evidence to bring about Mitch’s downfall, as she wants revenge for his sexual abuse of her. Back in Los Angeles, when he is informed that Terry is being held hostage, Frankie concedes to a meeting on Mitch's territory. Frankie then asks Charles for help, and Charles arranges to shadow Frankie with several of his karate students. Tank escorts Frankie to Mitch’s mansion the next morning, and when Frankie refuses to hand over the cigarette case, Tank shows him that Terry is outside, locked in a cage filled with venomous reptiles. Agreeing to get the case, Frankie is followed by three cars carrying Mitch’s goons, but when they get to Frankie’s car, Charles and his five pupils attack. After a fierce battle, Frankie and his friends prevail and return to the mansion. There, Frankie frees Terry, and Charles’ forces triumph over the remaining mobsters, after which Frankie demands that Mitch reveal the contents of the cigarette case. Mitch opens the miniature safe, but when Frankie plays the tape, he is dismayed to hear nothing but static and realize that Melinda died for nothing. Mitch laughs smugly and in a rage, Frankie pummels him and, outdoors, holds his head underwater in a pond. Charles pulls Frankie off the gangster, then departs with his students. Rushing to Frankie, Terry embraces him and after a passionate kiss, the couple walks away together.