John Smith has been happily involved in a bigamous marriage for five years. He lives with Stephanie in Finsbury and Michelle in Stockwell. Fortunately, for John, he's a taxi driver which involves varying shift work! Simple? Well, when John unwittingly becomes a have-a-go hero and the Finsbury and Stockwell police forces discover something suspicious in their paperwork, John's happy bubble is about to be burst. The action of the movie takes place during the next hectic 24 hours as John, with the assistance of his gullible neighbor Gary, rush between North and South London attempting to thwart the police and prevent the two loving wives coming face to face!

Rebecca Ryan has been working as an undercover agent for the Organised Crime Division (OCD) posing as a taxi driver, while investigating London's south-side mob. When she finds her young daughter Lynn brutally murdered she fears her cover has been blown wide open, so she turns renegade and begins a brutal campaign of vengeance against the mob she believes killed her daughter. As she trawls the seedy depths of London's underworld hunting down her daughter's killers, the lines between good and evil, right and wrong begin to blur as do her notions of justice and revenge. It falls to the world-weary OCD agent Darius Cuise and his newly-assigned, hot-tempered partner Abby Barrett to track down Rebecca and bring her in before all hell breaks loose.