The show features a masked prank caller (Kayvan Novak) who phones unsuspecting members of the public under various guises, in an attempt to confuse or 'wind up' the recipient. The audio is accompanied by on-screen imagery, consisting of pictures of people with crudely animated moving mouths, or by undercover filming in which Novak is in a street calling a company nearby, usually from inside a public phone booth or from a rickshaw. Occasionally short videos with actors are used instead of images; examples include a sketch where a man is robbing a bank, or one where men in hazmat suits are removing a pigeon from a bank vault. Novak is always seen wearing a red and white balaclava (black in the pilot) and sunglasses. In a new pilot for series 2, he is seen wearing a woolly hat with the initials G.P.R. and a black Mitre Premier League coat.