Midlevel corporate drone Reggie Perrin—although secure in his marriage, with a paid-for house, no children, a car and a comfortable living, he is dissatisfied with the grind of modern living, such as his daily, often overcrowded train commute—undergoes a mid-life crisis, keeping himself entertained by fantasies.
Whilst contemplating suicide, Reggie is at a crossroads and resigns from Groomtech, planning to lead a self-sufficient life growing his own vegetables. But money is tight, Nicola is fearful for her job and the best the Job Centre can offer Reggie is shelf-stacking. Mother is planning to marry Nicola's dad, and the therapist is rubbish. With Groomtech facing their largest decrease in disposable razors in years and Chris begging him to return, should Reggie sacrifice his principles and once more chain himself to the capitalist life?
David, the accountant who has just moved in next door, comes to call on the Perrins, who bore him with their troubles. Reggie tries unsuccessfully to sell his home-made bread at the local farmers' market but Groomtech are also in trouble. Sales are slipping and Anthony is the reluctant occupant of Reggie's executive office. When Reggie decides to bite the bullet and ask to be reinstated, he learns that Chris has been sacked and he's been made new managing director.
Determining 'not to lose touch with reality', Reggie makes sweeping changes, banning ties and introducing the wearing of slippers, a tea-lady and a bouncy castle to bounce ideas around in. He also gives strangers lifts in his company car. When the boss expresses disapproval, Reggie changes the firm's name to Grot and announces that it will make only useless things. Nicola, now sacked, is bored at home,spending her time mending basket chairs, whilst her father tells Reggie he has cold feet about marrying his mother.
The staff express doubt as to Reggie's viability selling his 'Grot' products – and indeed as to his sanity – but the goods fly off the shelves. The Groomtech chairman, hugely impressed, gives Reggie his next assignment — to cut half the staff. Nicola, feeling neglected as Reggie embraces work with great enthusiasm, initially rejects David after he makes a pass at her but still ends up ringing him. William, desperate to avoid matrimony, unsuccessfully tries to persuade Marion that he is gay.
Reggie resists the board's efforts to make him conform and stalls when told he must sack a staff member,an announcement which sends Anthony and Steve falling over themselves to keep in with their boss. Told that Groomtech will ultimately be sold and he will be sacked, Reggie plots revenge, including a naff and sexist advertising campaign featuring a leering former CEO.
After setting to work on David's house with a nail-gun, Reggie moves in with Anthony in his chaotic flat and exposes Nicola's infidelity in his best man's speech at his mother's wedding. Groomtech is sold but nobody is sacked. However, Reggie is demoted whilst Chris gets his old job back. Nicola returns to the flat where Reggie is enjoying the single life, to tell him that she now has a job and wants him to come home.
