Plot

Jay, Neil, Simon, and Will reunite in Australia for a holiday.

Neil, Will, and Simon receive an invite from Jay to join him in Australia on his gap year, who promises them it's ''the sex capital of the world''. With their lives now rather dull compared to their hedonistic school days and legendary lads' holiday, it's an offer they can't refuse. Once again, they put growing up temporarily on-hold, and embark on the backpacking holiday of a lifetime in an awful car, inspired by Peter Andre's 'Mysterious Girl'. Will soon finds himself battling with the lads to do something cultural, while they focus their attention on drinking, girls, and annoying fellow travelers.—Production

Friends Will McKenzie, Simon Cooper, Jay Cartwright, and Neil Sutherland have graduated from Rudge Park Comprehensive, where they were nowhere near being among the popular kids, but not total social outcasts either. Will's high-school life was made worse because of the antagonism between him and one of the school administrators, Mr. Phil Gilbert. Now separated, the friends' lives are outwardly not much better. Nerdish Will is attending uni in Bristol, where he has no real friends, though he's in denial of this. Simon, who is in a perpetual state of puppy love, is also at uni, but in Sheffield, so he could be with his girlfriend Lucy, whom he met on vacation in Greece. Simon doesn't want to admit that he really doesn't much like Lucy because of her controlling, violently-obsessive behavior towards him. Short of more than a few brain cells, Neil is working in a dead-end job. And all talk/no action Jay has moved to Sydney, Australia after breaking up with girlfriend Jane, a friend of Lucy's whom Jay met on that vacation in Greece and as always a bit embarrassed of because she was slightly overweight. According to Jay, he is now living in his Uncle Bryan's mansion, has a bevy of beauties catering to his every sexual need, and is the hippest DJ at the hottest club in town. Feeling down about their lives, Will, Simon, and Neil decide to take a four-week vacation to Australia: their first quest is to find and stay with Jay in the lap of luxury and fun. They soon discover that Jay's life is not even remotely close to what he reported. The friends' collective wants for the trip diverge when Will runs into Katie, whom he knew from prep school; she seems sexually attracted to him. Katie and the group she's traveling with are hip and outdoorsy, so Will tries to emulate them while he follow Katie around Australia. This not only puts him at odds with his friends but also with Ben, one of Katie's friends, who takes every opportunity to denigrate him in front of her. Meanwhile, Jay wants them all to spend their vacation at Splash Planet, a water park, but he doesn't tell them the real reason behind this choice of locale or the real reason he's in Australia. Through it all, Simon continues to negotiate his relationship with Lucy via Skype, but always ends up on the short end of the stick. As Will, Simon, Jay, and Neil spend time together and apart, their friendship is tested as they get into one misadventure after another.—Huggo

In the lead up to the Easter holidays, Will (Simon Bird), Neil (Blake Harrison) and Jay's (James Buckley) girlfriends have all broken up with them since the events of the last film. Simon is unhappy with his relationship with Lucy (Tamla Kari), who has become obsessive and abusive. Lucy removes all of Simon's female friends on Facebook and cuts up his clothes when he hesitates to vow that he will never cheat on her. Lucy spends a lot of time with Simon's best friend Pete.

Will is studying at university in Bristol while Simon is studying in Sheffield. Simon (Joe Thomas) and Will are unhappy and withdrawn at their respective universities. Neil is working in a bank, and Jay is taking a gap year in Australia. Will is ostracized by his peers at university.

Jay emails Neil when he and Simon visit Will, claiming that he is now a top DJ, owns a popular night club, lives in a luxury mansion and has daily sex with multiple partners, convincing them to visit him in Australia for their Easter holidays. The guys gather to catch their flight to Sydney. Will's mother gives him a sexual assault alarm as she is worried about him.

Neil cannot use electronic maps on his mobile as his telephone operator is charging him 20 pounds for every minute of internet usage. Once they arrive at the club, they find Jay in fact only works as a toilet attendant. While at the club, Will meets Katie (Emily Berrington), an old friend who is backpacking, and she convinces him to join her with her fellow backpackers in Byron Bay. Jay in fact lives in a tent in the front garden of his uncle Bryan's (David Field) house, there Simon attempts to break up with Lucy via a Skype call. Jay's uncles interferes and tricks Lucy into thinking Simon asked her to marry him, to Simon's shock.

The next day the four travel to a youth hostel in Byron Bay in a Peter Andre-inspired car, as Will wants to follow Katie there. He attempts to become friends with one of the backpackers, Ben (Freddie Stroma), but he is looked down upon because it is clear that he is a tourist and not a "traveler". After arriving, Will Skypes his mother and notices that someone else is staying at their house, which she denies and subsequently hangs up.

They travel to a youth hostel in Byron Bay and Will sings a bad cover of "The First Time Ever I Saw Your Face" to Katie, who seduces him at the hostel. Before they can have sex, Katie passes out, shortly before a backpacker enters and attacks Will for thinking he is engaging in sexual assault, setting off Will's own sexual assault alarm in the process.

The following day, the boys and the backpackers visit a water park named Splash Planet, where Jay intends to find his ex-girlfriend, Jane (Lydia Rose Bewley). It is revealed that Jay had traveled to Australia in the hopes of winning Jane back. Neil accidentally kills a dolphin by feeding it fast food, and Simon is attacked by some fathers after they mistake him for a pedophile.

The park staff tell Jay that Jane has found a new job in the vast outback, but they don't know specifically where he can find her. Will uses a water-slide, Neil soils himself due to IBS symptoms and his feces follows Will down the slide. Will is hit in the face by the feces, causing him to vomit uncontrollably and the pool to be evacuated.

Lucy tells Simon via Skype that Jane is working on a stud farm in the remote settlement of Birdsville, and the boys intend to drive there. Will however decides to follow Katie instead. He struggles to fit in with the 'spiritual' activities of the travelers and discovers that Katie is seeing multiple people at once, launching him into one of his foul-mouthed tirades towards them, which leads Katie into having sex with Ben.

The boys leave Splash Planet, and Jay opens up about wishing to reconnect with Jane. Lucy tells Simon over Skype that Jane works at a horse farm in Birdsville. The boys prepare to drive there, but Will, angry and dejected over the Splash Planet incident and towards his friends' treatment of him, stays in Byron Bay in the hopes of starting a relationship with Katie and becoming a traveler.

The next day Will leaves the hostel and by plane travels to reunite with his friends in Birdsville. While driving to Jane's workplace, their car runs out of petrol in the middle of the desert and the four unsuccessfully attempt to find a source of water or help. Desperately thirsty, Simon resorts to drinking Neil's urine, but Neil is too dehydrated. The group hold hands together as they realize that they will most likely die but are rescued by Jane and her co-workers. It is revealed they have only been stranded for two hours. Jane realizes how far Jay came to win her over again, and although she is touched by the gesture, she does not take him back.

Back at Jay's uncle's house, the boys find that their parents have traveled to find them after hearing of their 'near-death' experience. The boys are shocked to find Mr Gilbert (Greg Davies) (their old head of sixth form and Will's nemesis) there too, and Will's mother Polly (Belinda Stewart-Wilson) announces that she and Gilbert are in a relationship, to the abject horror of Will and amusement of the other three friends. Meanwhile, Jay finally shows some backbone and slaps his uncle for insulting Jane's weight, instigating a fight between his uncle and father. Over Skype, Lucy breaks-up with Simon because she is now in a relationship with his university 'best friend' Pete (Adam Nagaitis), which Simon responds to by cheering and abruptly hanging-up on her.

The four boys decide to travel to Vietnam. As they return to England, Neil begins a relationship with one of the travelers while Will's mother reveals that she and Gilbert are engaged. Will attempts to run back to the plane but is wrestled to the ground by security.