Tom, a geologist, and Gerri Hepple, a counsellor, are an older married couple who have a comfortable, loving relationship. The film observes them over the course of the four seasons of a year, surrounded by family and friends who mostly suffer some degree of unhappiness.
Gerri's friend and colleague, Mary, works as a receptionist at the health centre. She is a middle aged divorced single woman seeking a new relationship, and despite telling everyone she is cheerful and happy, she appears desperate and depressed. She often seems to drink too much.
The Hepple's only son Joe, is 30 and unmarried and works as a solicitor giving advice on housing.
In the summer the Hepples are visited by Ken, Tom's old friend from his student days. Ken is overweight, eats and drinks compulsively and seems very unhappy. Tom and Gerri host a barbecue in Ken's honour. Mary drives her newly bought car to the party, but gets lost and arrives late. Having had some wine, she flirts with the Hepple's son, Joe , who remains friendly but does not reciprocate. After the party, Mary reluctantly gives Ken, a lift. He makes a clumsy sexual approach and Mary angrily rejects him.
Months later in the autumn, Mary is once again at Tom and Gerri's home. Joe arrives with a new girlfriend, Katie. Mary appears rude and hostile towards Katie, which is not appreciated by Tom and Gerri. This leads to a rift between Gerri and Mary.
Time moves on to winter and Tom, Gerri and Joe attend a funeral for the wife of Tom's brother, Ronnie. Towards the end of the service, Ronnie's estranged son, Carl, arrives late and angrily questions why the ceremony has not been delayed for him. Later at the reception at Ronnie's house, Carl becomes aggressive and walks out. Tom and Gerri invite Ronnie back to London to stay to with them for a while and Ronnie agrees.
While Tom and Gerri are at their allotment Mary arrives unannounced at the Hepple's home and persuades Ronnie to let her in. Her car has just been written off and she is upset. The two have a cup of tea then a desultory chat before Mary falls asleep on the couch. When Tom and Gerri return they are unhappy to find Mary at their house. Gerri explains to Mary that she feels let down by her earlier behaviour towards Katie. Mary apologises and weeps. Gerri gradually extends a degree of warmth to Mary, suggesting that she should seek professional help, and the two women set the dinner table. Joe and Katie arrive, their relationship still appears strong and happy. The Hepple family enjoy dinner together. Mary eats with them but appears lost and uncertain.