Martin Muffett is an engineering student at Leicester University in early 1989, aged 22. He rents a room at the home of George and Pauline Mole. Being highly practical, as befits his chosen career, he re-hangs all the internal doors and gets everything working smoothly. Martin soon begins an affair with his 45-year-old landlady, Pauline, and cares nothing about the age difference. Little Rosie Mole soon accepts Martin as part of her family, for a while preferring him to her brother, Adrian, who is living in Oxford at the time.
Adrian is shocked by his mother's latest adultery, especially since he regards Martin as uncultured. Martin rebukes him thus: "Maybe you don't rate me because I am an engineering student. But I'll tell you something mate. I don't rate floppy-wristed so-called intellectuals who fat-arse about reading books all day, right? Your father is a lazy sod, and so are you."
George and Pauline divorce for the first time, and George moves out. Despite the disapproval of Martin's parents (he is their only child), Pauline and Martin are married, on Christmas Eve 1989. Their wedding is marred by the discovery that Adrian, who was giving his mother away, has a severe infestation of headlice.
The marriage is a happy one at first, and Martin continues his studies, although he begins to accumulate uncomfortable debts. By late 1991 he is regretting his rush into marriage, while Pauline becomes frantic over bills, which threatens to swallow Martin's tuition money. Adrian feels obliged to settle some of them for her.
Next February Martin meets Adrian's girlfriend, Bianca Dartington - herself an engineering graduate, close to his own age. They bond immediately, and soon fall in love, abandoning their respective partners for each other. Adrian and Pauline are both heartbroken (although Pauline soon reunites with George).
Martin and Bianca make plans to set up an engineering partnership, "Dartington and Muffet." This is the last we hear of them.