Rod Hamilton, a wealthy jazz aficionado, throws a big one-year wedding anniversary party for Aurelius Rex, a bandleader and pianist, and Delia Lane, a retired singer, in a
Thames-side warehouse in
London that he remodeled to create a space for all-night parties and jam sessions, which he cannot hold at his house in upscale
Mayfair. Johnny Cousin, Rex's drummer, has been trying to start his own band. He has arranged for Rod to fund the venture, and also has interested Lou Berger, a powerful booking agent, but the support of both men is dependent on the truth of Johnny's claim that Delia will be his vocalist. When Delia tells Johnny at the party that she has decided not to come out of retirement because she fears it will cause tension in her marriage, Johnny initiates a complex series of machinations intended to break up her and Rex. Johnny decides to try to make Rex believe that Delia is having an affair with her friend Cass Michaels, an alto sax player in Rex's band and Rex's
road manager. Knowing that Cass is a recovered drug addict, Johnny gets him to smoke marijuana, and then tells him that Berger does not think he should be managing Rex's tour, which results in Cass blowing up at Berger and Rex firing him. Then, Johnny uses Rod's recording equipment to record Cass talking with him and then Delia, and edits the tape to make the conversations – which are about how Cass feels about his girlfriend Benny and how Delia will try to get Rex to forgive Cass – seem as though they are about Cass and Delia's affair. He drops hints to Rex that play on Rex's fears of losing Delia, and Delia's performance of a song, rehearsed solely for the party as a surprise for Rex, furthers Rex's suspicions that she is unhappy at home. Finally, Rex decides to listen to Johnny's doctored tape. He attacks Delia, strangling her, and then assaults Cass when he tries to intervene, sending him over the railing of a balcony in the warehouse. In front of the whole party, Rex accuses Delia and Cass of infidelity. When Emily, Johnny's long-suffering wife, asks Rex why he is behaving this way, Rex tells her to ask Johnny, and Emily breaks down and emotionally proclaims that Johnny is "a liar. He never told the truth in his whole life." Rex mentions the tape, and Benny figures out that Cass was talking about her, not Delia, which the seriously-injured Cass verifies. His plot exposed, Johnny runs out of the room, pursued by Rex, who is kept from strangling Johnny to death by the appearance of the bruised – but alive – Delia. Rex slowly walks back to Cass, who assures him that "Everything's cool", and then leaves the warehouse. Delia runs after Rex, and he stops, but when he sees the marks of his fingers on her neck, he continues to walk away. As an ambulance arrives, Delia chases him down again, and he stops once more. Cass is loaded into the ambulance and Benny goes with him. All of the other guests leave, but Johnny stays behind, noodling on the drums. Emily tells him it is time to go and says, "I love you", to which he replies: "Don't you understand, I don't want to be loved...I love nobody. Don't even love Johnny...Go find somebody else to love." As Emily, and then Rod, exit, leaving Johnny alone in the nearly-dark warehouse playing a frantic solo on the drums, outside, Rex and Delia walk along the embankment, their arms around each other's shoulders. ==Cast==