Tim Bisley (Simon Pegg) and Daisy Steiner (Jessica Stevenson) meet each other in a cafe and are soon planning on moving in together. The only problem is the advert for the flat they're planning on renting is for a professional couple only. Tim suggests they pretend to be a couple. They do this and are soon living in the flat below the Landlady and above the strange man in the basement.

Once the new roommates have finished unpacking, Daisy is looking for any excuse not to sit down and do some work. So, she persuades Tim to throw a housewarming party, complete with the paperboy as a guest, a homemade foil mirror ball, and Prefab Sprout on the stereo!

Brian receives an invitation to the new performance art show of his ex-partner Vulva. He plucks up the courage to go, along with Tim and Daisy, but is treated horribly by Vulva. Tim comes to the rescue after his violence tendencies are brought out by a bowl of Twiglets. Meanwhile, Daisy has a magazine interview which doesn't go too well, and the experience leads her to try a little performance art of her own.

After being dumped by her boyfriend, Daisy decides she needs companionship and heads to the pound to get herself a dog, not realizing that Tim is scared of dogs. Meanwhile, Tim and Mike go paint balling, and meet up with Duane Benzie, the man who Tim's ex girlfriend Sarah left him for.

Colin goes missing when Tim takes him out for a late night walk, and at first Daisy suspects that Tim has deliberately got rid of him. Later, they receive a note tipping them off that Colin has been dognapped by an evil vivisectionist! They gather the troops and start a rescue mission.

Tim's friend Tyres stops by the flat and invites the two "friends" out for a night of clubbing. They decide to take him up on the offer, and round up Mike, Brian and Twist to join them.

Tim's ex Sarah calls him up and wants to get together, Tim is over the moon at the idea of them getting back together, though Mike and Daisy are less impressed and worried about him getting hurt again. Meanwhile, Mike is up for re-evaluation for the TA, and is delighted to be let back in. Tim meets up with Sarah and it turns out she really does want to try again with him, but at the last moment he sees sense and declines, not wanting to give up all his has with Daisy and his friends.