Louise's mum, Eileen, turns up and announces that she's moving in, after having been dumped by her toyboy. Karen is far from happy with this. Donna is trying to make an impression on Sam's friends but does so by insulting them. Louise and Karen go out with Eileen who makes a show of herself by doing lesbian dancing with her daughter to attract men. Sam gives Donna an ultimatum - it's Karl or him.

Richard, Louise's boss at the restaurant, is assumed to be gay, but appearances are not what they seem when he shares a bed with Donna. Louise decides that it's time to take the bull by the horns and have sexual relations with a man and asks out Oleg from the restaurant. Karen gets run over and decides to give up drinking, which turns her into a demented, sweaty, man-repellent.

Donna wonders how her 30th birthday will go with the electricity turned off, and with Karl no longer sounding miserable she begins to feel insecure. Karen gets Louise to organise Donna's present on the internet, but Louise accidentally gets addicted to online porn instead. Karen is owed money by Mark, who, she finds, has inconveniently died.

Karl tries to kill himself but changes his mind at the last minute. Donna discovers him hanging by a noose and saves him. At a party, Karen is being stalked by Mark, who she really cannot stand. The girls persuade Donna to let a friend of Louise's called Tanya look after Karl. The party is a disaster, and Donna returns to find Tanya's relationship therapy session with Karl has been less than helpful.

Louise falls in love. Unfortunately it's with 'Thingy', Karen's conquest from last night. She can't believe that Karen didn't get his number but spots an opportunity to bag herself a man. Donna is looking for work and persuades Karl to set her up with an elite employment agency. Karen quits teaching to live the life of a free-spirited alcoholic but the realisation that hanging out with old men and wearing random strangers' knickers isn't all it's cracked up to be quickly results in a change of heart.

On her hen night, as she watches Louise stage dive into a crowded dance floor and Karen recreate the Bacardi ad on the club bar, Donna realises with absolute drunken clarity that single girls have more fun. In this state of inebriation she declares the wedding off. Karl responds by running into the kitchen wall and begging Donna not to leave him. Donna moves in with Karen, and so life begins.