In Beecham House, a retirement home for former professional musicians patterned after the real Casa di Riposo per Musicisti founded by Giuseppe Verdi, Reg Tom Courtenay, Wilf Billy Connolly, and Cissy are retired opera singers who had often worked together. Among the residents are Cedric Livingstone, a former director, and diva Anne Langley. All the guests in the retirement home are suffering in varying degrees from the ailments that old age can bring, but they remain engaged in their former professions, including lecturing and introducing younger people to music. Finances threaten closure of the home, but proceeds from a yearly gala concert on Verdi's birthday hold hope for a continuation. However, Cedric has become desperate because some of the most prominent singers have either died or decided not to participate at all. Reg, Wilf and Cissy were in the cast of a very highly rated recording of the opera Rigoletto, which includes a famous quartet for soprano, mezzo-soprano, tenor and baritone ("Bella figlia dell'amore"). This version is very prominent among opera buffs as the definitive Rigoletto of the post-war era.
Reg is shocked to find his former wife Jean Horton to be the missing soprano of the Rigoletto recording, learning that she lives at Beecham House. Reg is angry not to have been warned nor consulted, as their parting was on very sour terms. At first, Jean [Maggie Smith] tries unsuccessfully to mend things with Reg. In the ensuing conversations, her infidelity arises, as well as her past marriages, but Reg comes to understand that it is all in the past.
In the meantime, Cedric has devised a plan that could work but has one flaw. He meets with Wilf, Cissy and Reg to put his idea to them. His hope is to convince them to re-form the quartet who sang on the famous recording and to sing it again for the Verdi Gala concert, hoping that it will sell enough tickets to save the home. Reg is skeptical but agrees, having overcome his issues and problems with Jean living at the home and being in such close daily proximity. Wilf persuades the doctor in charge to allow them a night out, resulting in Reg, Wilf and Cissy inviting Jean to dinner. Blissfully unaware and thinking friendships are mended with the past forgotten, Jean accepts the invitation. However, she is harder to persuade, for she vowed never to sing again after retiring, resulting in her getting angry and storming out of the restaurant.
The following morning, Cissy brings Jean flowers from the garden to cheer her up and asks if she wishes to discuss the quartet. But Jean does not want to take the flowers and beats Cissy with them, which aggravates Cissy's already delicate senile condition. Jean feels horrible for her behaviour and attempts to apologise but is not able to see Cissy and instead sees an old fling in the infirmary. He convinces her to appear in the Gala, even if she has to do magic tricks. Jean is finally able to apologise to Cissy and is persuaded to sing in the quartet from Rigoletto after learning that Anne Langley will be singing Vissi d'arte from Tosca as a finale, unless the four of them sing together, in which case, they will be given the honour of performing last. The group prepares for their performance, but moments before their curtain call, Cissy gets very confused and attempts to walk out the door, saying that she has to go back to her family. But Jean manages to salvage the situation. During her conversation with Cissy, Jean expresses regret for all of her bad behaviour towards Reg and admits that she is still in love with him. Reg overhears it.
As the recital is about to start, the director of the home is amazed at the energy displayed by the home's guests. The idea of rehearsing and playing before an audience has rejuvenated the home and the quartet. Prior to going on stage, Reg again asks Jean to marry him. As the quartet individually enters the stage to a rapturous applause, Reg stands next to Jean. Jean asks Reg if he was serious, and he replies affirmatively. Jean accepts and takes Reg by the hand.
