A new batch of students arrive at Roundview College, friends Freddie, Cook and JJ all falling for Effy's charms. Two identical twin sisters,Emily and the dominant Katie also arrive. Effy sets the three boys a dare with herself as the prize for the winner,which results in her having sex with Cook in the college nurse's office.

Hoping for a night of wild abandon, Cook invites everybody to his birthday party at his uncle's pub but the party collapses after Effy's friend Pandora throws up. Cook manages to persuade everyone to gate-crash a party being thrown to celebrate the engagement of a girl called Kayleigh, but he falls foul of her father John White, a drugs baron to Madame Greta's brothel; he again encounters John White and a fight ensues and White threatens to kill Cook if he sees him again.

Thomas arrives in Bristol from the Congo with his parents to follow him, but after sleeping in an empty flat he falls foul of its owner, John White, who demands money. Pandora takes a liking to him and helps him by giving him dope to sell, but unfortunately they find they are selling it on White's turf. White threatens Cook again, but Thomas steps in to champion him and defeats White in a chili-eating contest. However, when Thomas's mother turns up, she is appalled and demands he return to Africa.

Pandora throws a birthday party, but her strict mother Angela forbids the use of alcohol so Katie makes some cakes laced with ecstasy; unfortunately, Angela eats one and passes out. This leads to a row between Pandora and Effy, and Effy ends up having sex with Cook again. The next day, it's Pandora's turn to enjoy Cook's sexuality, but Effy cottons on to what has happened, while Emily is observed kissing Lesbian Naomi.

Freddie's sister Karen is entering the Next SexBomb contest but he disapproves of her trying to win the sympathy vote because their mother is dead. JJ tells him Cook wants to see him but he is tired of doing what Cook wants and goes to see Effy to reveal his feelings though she rejects him. Despite having turned their shed into a dance studio,Karen loses the contest,thanks to Cook persuading the local pub customers to vote against her. Freddie decides he will definitely explain to Effy how he feels about her but finds she is with Cook.

The affair between Naomi and Emily intensifies. Cook is running for student president and challenges Naomi to sleep with him if he wins. He does win, but they get no further than kissing. Meanwhile, Freddie tells Naomi that he has fallen out with Cook and loves Effy. Naomi resists the advances of her teacher Kieran to have sex with Emily again, then finds Kieran in bed with her mother. She ends up holding hands with Emily through a catflap.

JJ visits his psychiatrist after feeling 'lost and confused' about his life and friends. He is given lots of medical drugs to calm his Aspergers. He finds that Emily goes to the same clinic as him and they spend some time together; Emily calms JJ down,admits to him that she is a lesbian, and offers advice to help him sort out his numerous issues. JJ and Emily then visit Freddie and walk in on him having sex with Katie. During the confrontation, JJ accidentally informs Katie that Emily is a lesbian. Later, JJ visits Effy and asks her to stop interfering in his friendship with Freddie and Cook. JJ then visits Cook and discovers that he is also having casual sex with Pandora. Later, the group goes to a You Love Her Coz She's Dead gig, where Cook is beaten up after getting into a fight with some ravers. Before the chaos Effy and Naomi have a heart-to heart-outside, where Effy reveals that she knows about her and Emily. Naomi is hit by a wave of relief when Effy states that she does not mind if she is gay or not. Cook has taken JJ's Stun pills; they calm him and also make him tell the truth. Cook reveals that Effy loves Freddie back, but she cannot admit it and does not want a serious relationship. He bizarrely even admits to being genuinely hurt by this as he loves Effy too before admitting to having sex with Pandora, which Thomas overhears. JJ invites an upset Emily back to his house for the night, so she does not have to go home and face Katie. The next morning they sleep together; Emily tells JJ it is a "one-time charity event."

Effy is unhappy when she sees that everybody seems to find Katie more popular than herself,even Freddie. Katie is even more popular when she invites everybody to a party - except Cook,who gate-crashes it anyway. At the party Effy gets back her status as the focus of attention when she brings some magic mushrooms,but she ends up taking a bad trip and fighting with Katie,whom she puts into hospital. She tries to visit her but is rejected and wakes up in a stolen car driven by Cook.

Since Katie won't leave the house, Emily impersonates her to take her exam and meets Naomi, who tells her that she is going to Cyprus for the summer but declines Emily's invitation to accompany her to the end-of-term ball, though she does turn up on her own. At the ball, the sisters fight when Katie learns that Emily went with JJ, but Emily resists the temptation to hit her sister, instead declaring her love for Naomi and walking off with her. Pandora and Thomas are also able to get it together.

Effy and Cook go into hiding with his father, but Effy contacts Freddie, who turns up with JJ, though it is Freddie with whom Effy ends up sleeping. Cook asks his father if he can leave the country with him on his boat but Cook, Sr. threatens him and must be restrained. Eventually Effy and the boys take the boat back up the river after Cook pushes his father overboard. But despite Effy's evident feelings for Freddie, who ends up with whom is inconclusive.