Jeremy takes Mark on a stag weekend, with a rented canal boat. There, they meet two sisters, Aurora and Lucy, and their father. Jeremy falls in love with Aurora, whilst Lucy becomes sexually attracted to Mark. The father offers Mark a job in India, a way out of his impending marriage to Sophie, whilst Jeremy accidentally kills, and then eats a bit of Aurora's dog.

It's Mark's wedding day. He is torn about whether he should go through with it or not. Jeremy discourages him but Mark continues. On the way to the reception, Sophie breaks down and runs away. Jeremy comforts Mark as the 'El Dude Brothers' are reunited.

Jeremy plans to throw a secret magic mushroom party in the flat, where he hopes to seduce his ex, Big Suze. But when Mark suddenly comes home from work with gastric flu, Jeremy's plans go to pieces.

Mark worries he and Sophie are drifting apart and proposes. Elsewhere Super-Hans decides to give up drugs, and Jeremy once again gets intimate with past love Big Suze.

Jeremy and Nancy are getting married, for visa reasons. Mark, determined to save his friend, will do whatever it takes to stop them...

Jeremy is hired by an old school friend to make a soundtrack for a film he's making. Mark makes a new friend at work who turns out to hold a fair amount of prejudice. Meanwhile, Sophie spends time with Jeff.

Mark becomes depressed about Sophie living with Jeff, but Jeremy is not sure that self-mutilation is the answer. Besides, Jeremy and Jeff are getting on horribly well.

Jeremy gets called for jury service but soon complicates things by falling for the defendant. Elsewhere, Mark & Sophie go clubbing.

In order to avoid spending time with Sophie, Mark gets a gym membership. Whilst there he discovers that Jeremy's ex-wife Nancy is working there. Mark tells Jeremy who then becomes desperate to get back together with her. He decides to take a job as a cleaner at the gym and sets about stopping her from dating Mark's personal trainer Matt.

Jeremy meets his hero, techno musician Russell "The Orgazoid". He ends up working as his handyman, which leads Mark to become suspicious, as it seems that Jeremy's job consists of making smoothies for him. Meanwhile Mark meets Sally at his school reunion, one the few girls who actually ever liked him. It turns out that she has married one of Mark's childhood tormentors, Foz. Mark decides to try and seduce Sally whilst Sophie is away on a business trip.

Dobby is offered a job in New York by ex-boyfriend Simon. Uncertain about the offer, Dobby suggests that she and Mark spend a weekend in the country. The perfect time, as far as Jeremy is concerned, to get a few things off his chest.

It's the last ever Peep Show from the El Dude Brothers. Jeremy is turning 40 - and it's hitting him hard - while Mark makes an audacious attempt to win the woman of his dreams.

In the last episode of the series, death and terminal illness prove to be the keys to romantic success for Mark and Jeremy. Jeremy gets in with the Christians and Mark finds the perfect venue for a first date with Sophie - a funeral. Everyone's having a great time until the paramedics arrive.

Mark and Sophie are finally beginning to go steady when Sophie is moved away from London for work. Mark is devastated, so Sophie offers phone sex as a solution, which Mark nervously accepts. Meanwhile, Jeremy is forced to consider getting an old friend sectioned.

Mark and Sophie return to work, while Jeremy renews his acquaintance with the depraved Super Hans, in yet another filthy, funny episode.

Mark gets into online gaming and live role play with Dobby and wonders whether she may be The One. Meanwhile, Mark and Sophie finally sort out their annulment. Jeremy joins a cult.

Mark makes a final play for Dobby, the object of his desires. Meanwhile, Jeremy meets a new love, Russian émigré Elena. Both guys are determined to impress, but one of them is an expectant father. And when the pregnant Sophie spills the beans, both Mark and Jeremy's worlds change forever.

Jeremy and Hans publish their first track on a football video on YouTube, but they disagree of the authorship of the lyrics. Mark takes his kid Ian for playtime in the Kid Kave, and tries to balance between miserable stability with Sophie, or a potential relationship with April.

Mark has invited his parents over for Christmas dinner. Everything has been planned down to the last detail but Jeremy has become over excited and Dobby and Super Hans show up as unexpected guests.

Jeremy's love life takes a surprising turn, as Mark is dealing with his own matters of the heart.

Jeremy tries to wow Toni with his new job in a music studio while Mark gets passed over for promotion in favour of Sophie, and goes slowly round the twist. They then attempt to solve each other's problems with the help of phone stalking and pepper spray.

Jeremy wants to get closer to Nancy so he tries to impress her by joining in her volunteer work which involves working in a soup kitchen for the homeless. Mark manages to get Johnson to think he is an alcoholic.

Mark, determined to forget Sophie, makes an effort to go out with April - but manages to blur the line between enthusiastic new boyfriend and stalker. Jeremy joins a new band, Executioners Bong, but insists that he is neither a roadie nor the equivalent of Bez.

It's not so long since Mark's new bride Sophie stumbled from the car, looking in appalled fascination at her husband of ten minutes and sobbed, "He's horrible!" As we return for the fifth series of this engagingly filthy comedy, Mark (David Mitchell) is getting drunk and maudlin on wedding champagne as his flatmate Jeremy (Robert Webb) urges him to go out on a double-date: "Beggars can't be choosers, she's an actual woman." Mark - remember, this is a man who once based his romantic strategy on the Siege of Stalingrad - arms himself with a copy of the Friends of the British Museum magazine and goes forth again to search for love.

Newly promoted Mark decides to enjoy his additional power and wealth by splashing out on a boiler, a 'creamy elephant' sofa and by finding Jeremy a job in the office. Things are also looking promising for Mark in his pursuit of Dobby, the company IT girl. However, a routine fire drill puts his plans into total disarray.