It is Christmas time and the day of the school nativity play. Eric's son Brian has a tiny part in it as sheep number six but Eric thinks that even this could prove a landmark in the boys development especially given that Brian's sole achievement to date has been to put toy cars in his mouth. But then Brian's never been on stage before and there's no way of knowing how he will react to the pressure.

Although he's supposed to be writing a speech for work, Eric spends his day irritated that everyone else in the world is getting some. But his hopes are lifted when an old college fling calls him out of the blue and wants to go out. Problem is, Eric promised Claire that he'd take her to the non-allergenic carnival. So Eric, Claire, and his former flame are off to the carnival. At the end of the evening, Eric takes the old friend home, and the pair endlessly attempt to have sex -- quietly. As if that's possible....

When Eric needs to get £35 to pay the window washer, he is forced to break Claire's piggy bank to get the money. In doing so, he finds her diary and discovers she wants a pony. Finding that a pony is out of his price range, he gets a smelly donkey with removable ears. When Claire insists the donkey go in the Gymkhana at school, Eric has no choice but to enter the old thing in the competition. Meanwhile, Brian and Maria raise havoc with a chemistry set.

Drowning in a sea of debt, Eric desperately seeks to improve his standing with his boss in the last ditch hope of a pay rise. So he volunteers to entertain a troublesome but important client, the Chairwoman of the potato development board Mrs Bont. Come the evening in question everything for once seems to be working out well. The table is laid, the food is out, the guests are about to arrive. Then Eric finds out he is just one potato short.

A Japanese man agrees to work with Eric's company -- but he stipulates everything must be ""clean and tidy."" So Eric leaves it up to Alison to clean the office while he goes home to take care of the rat that crawled up through his drainpipe. But, as usual, Alison spends her day gabbing on the phone... Eric arrives at home to find that the rats have multiplied and the exterminator he's hired is useless. And to make matters worse, Liz shows up with her boyfriend picketing for ""rights for rats."" Meanwhile, Maria takes the children to the amusement park and ends up in a high-speed police chase....