Steve and Susan's relationship is drifting into a new phase. They are beginning to get on each other's nerves. A bizarre set of misunderstandings brings on a crisis.
As Jeff's 30th birthday approaches, his new boss Julia Davis questions the girls about whether one should kiss a junior work colleague, while Jeff admits to the lads that he had a close encounter of the Nat (Nose Avoidance Tilt) kind in a stationery cupboard at work.
Patrick has boasted to his business associate, Ivan, amongst other things that he has a wife, and when Ivan comes to the bar, Patrick presses Sally and then Susan into pretending to be his wife. Things turn awkward when Steve proposes to Susan while she is pretending to be faithfully married to Patrick. Meanwhile, Jane is invited on a dinner date by Bill, a man she chatted up in a pub, but makes an unfortunate choice of clothing for the evening.
It's one year since Steve and Susan's first date, and he is dreading questions about their future. And then a wedding invitation drops through their front door. Patrick meets an ex who appears to fail to recognize him.
Jane gets the sack as a traffic reporter for a local radio station, and decides on a new career in children's entertainment. She starts rehearsing with a pink snake hand puppet, which turns out to have an unstoppable ability to tell the bald truth. Patrick is trying to dump his latest girlfriend Lynda, but when she says she's interested in a threesome, he desperately starts backtracking.
Following their disastrous encounter, Patrick seeks reassurance from Steve & Jeff, who explain to him the theory of the Melty Man, and Sally seeks reassurance from Jane & Susan, who try to comfort her with their own "failure" experiences.
When Steve pops into Susan's flat, he accidentally sees Sally's naked bottom. This incident leads to dilemmas and awkwardness all round, which are dealt with in the classic sequence outlined by Jeff: the prickles (an embarrassed silence), the blurts (talking too fast), followed by the "head laugh".
After watching an embarrassing program on TV with Susan, Steve bumps into his dream celebrity, Mariella Frostrup, in the bar, but it is not the dream encounter he might like, as she pours her drink down his trousers. Jane and Sally's attempt to make friends with her get him into more trouble as he then has to have dinner with Susan's liberal-minded parents, which turns into a nightmare as misunderstandings multiply.
Jeff finally gets to speak to Chrissy, the woman on the train whose leg he has been fancying for days, and tells her that he only has one leg, a lie which becomes ever harder to undo. Meanwhile, Sally is dating a "surgeon" called David, and Jeff wonders whether it would be easier.
