All the curtain-twitching horror stories about sexual habits in suburbia are laid bare in this new comedy-drama Bonkers. The six-part, sex-packed series stars Liza Tarbuck as a likeable schoolteacher, Helen, who's married to Tony, a struggling soap writer played Mark Addy. On their 20th wedding anniversary her life is thrown out of its comfortable but messy domesticity when her 19-year-old ex-pupil Nicole announces to the anniversary partygoers that she and Tony have been having a affair for three years. While her marriage and life appear to be in tatters, somehow something completely bonkers happens involving a film star called Felix Nash which leaves her feeling on top of the world.
Helen has forgotten her 20th wedding anniversary and, when she's reminded of it, she hastily throws a party where all kinds of revelations come out such as Neighbour Jeremy who is married to the local GP Harriet is in love with Helen, Helen's youngest brother Marcus who is married to Imelda who wants to get try experiment with different things in bed, Helen's older bother John is engaged to Debbie, who wishes he was a bit more well endowed, and Helen's son Tim is having too much sex with the wrong people but Helen and Tony think they have a solid marriage until a former ex pupil shares the biggest secret of the night.
Helen's delighted to find herself living with film star, Felix Nash. Felix, on the other hand, is growing desperate he finds himself unable to leave the house and resorts to drastic measures in a bid to escape. John turns up at Helen's house after burning his own house down when he found Debbie in bed with Tim, and his sister is only too happy to let him stay. John can't see Felix and begins to think that Helen's going mad. Meanwhile Marcus finds out that Imelda thinks he's gay and Imelda discovers that Marcus thinks she's a lesbian. Which gets her thinking...
Helen's headmaster and neighbour, Jeremy, clearly has the hots for her but she only has eyes for film star Felix. In a bid to seduce Felix, she cooks a romantic meal and sends Tim and John to the pub. Curious, Tim creeps back to the house to spy on her. Meanwhile, Tim continues getting up to no good with Mrs. Wadlow and Mrs. Cavanagh, while Aunt Imelda is off on a lesbian blind date. John, meanwhile, is becoming more and more wound up. Has he got something to hide?
John threatens to throw himself off Helen's roof and when Marcus goes to rescue him he ends up getting stuck up there too. Helen gets tired of Felix and angry with Tony, she decides to invite Jeremy to dinner and when Jeremy returns home he gets the shock of his life. Elsewhere, Imelda sets up a strange date and Tony is still trying and get his life back on track. Later, John gets hauled down to the police station, when some of Debbie's belongings turn up.
Imelda realizes she wants to make a go of her marriage, but Marcus has had a realization of his own. Helen is forced to come clean to Tim when he catches her talking to herself again, and Marcus is sure he's spotted the missing Debbie. Meanwhile, Tony has an anxious meeting at work.
In the series finale Tim has to escape two angry husbands when they find out he is the local gigolo, Nicole has some news for Tony and Harriet has got to come clean to Jeremy about something.