Martin can't stop talking about his newfound sex life. Matthew confesses to Mandy that he's terrified of going out of the house, so she arranges for him to meet her psuchologist friend Jason. Unknown to Matthew, Jason is gay and, after talking to Matt, he tells Mandy that he's fallen in love. Mandy starts an Italian evening class and her tutor, Mario, shows an interest in her. When she tells him that she's celibate, he misunderstands and thinks she's trying to say that she's a virgin. Then Martin and Mandy discover Matthew in bed with Jason....

Martin meets a nurse named Clare, who agrees to go out with him. She tells him that she wants to lose her virginity. After a few mishaps, Martin finally makes love to her. Meanwhile, Matthew decides to stay in bed, and Mandy resolves to become celibate.

Martin realises that Clare left him because he's boring. He starts a voluntary job, working for a telephone helpline for distressed people. He gives his home phone number to Tesni, one of the helpline's clients. She rings the flat while Matt is at home alone and, thinkng that Matthew is Martin, she threatens to commit suicide unless he visits her home. Matt goes round to see her but, when he gets there, he collapses and has to be rushed to hospital. Martin arrives at the hospital, looking for Clare. Mandy also turns up, with her latest boyfriend. Matt meets a red-haired student named Susie and falls in love with her.

Jason manages to persuade Matthew to go out to the park and, later, to a gym. WhenMatt shows Marco a video of Mandy having sex, Marco realises that she isn't a virgin and decides he's no longer interested in her. Meanwhile, Martin has become very insecure about his relationship with Clare. A combination of paranoia, jealousy and drink leads him to make a complete fool of himself. Matt finally manages to go out on his own, on a trip to a local shop. Unfortunately, the shop is raided by a masked gunman, so Matthew decides that he'll never go out again!

Mandy is visited by her old boyfriend Stoat. When the flatmates discover that he's escaped from prison, Stoat ties up Matthew, Martin, Jason and Clare. He takes Mandy into her bedroom and they end up having sex. Mandy ties Stoat to the bed and gets his gun, then releases her friends. Clare tells Matt that Jason is gay. Jason leaves and Clare dumps Martin.

Martin is very depressed about the end of his relationship with Clare; Mandy has a close encounter with Brian Kennedy, a lecturer from her old university; Martin and Mandy find out what Matthew has been writing in his secret journal.