With his high-flying sister Theresa perennially busy, postman Paul has always been happy to be there for his parents, and with mum Shirley now in long-term care, she and dad Tommy need Paul and his wife Lisa more than ever. When Shirley asks Paul to move in with Tommy in the big family home, it seems to make sense for everyone; Paul, Lisa and their two boys are cramped in their tiny rented house. But Lisa worries about the long term - when both parents have died, they'll have to move out or find the money on a postman's pension to buy out Theresa. No problem, Tommy says; he'll just sign the house over to Paul and Lisa - he believes Theresa won't mind, as she has her own big house in Cheshire worth twice as much. But when Theresa visits, she is horrified; she has worked hard all her life, and her reward is to lose her share of the family home..? Upset, as a parting shot, Theresa tells Paul a family secret that turns his world upside down.