A Columbian drug cartel, the Chala Cartel, is operating in the UK and the good guys are trying to stop them. When plans turn up that reveal that the cartel is attempting to smuggle missiles into the country, MI5 gets involved in the form of Tom.
Tom rides along on a customs op. Things get rough and all but Tom are killed. MI5 dig deeper and dig up that the cartel has some high connections through the oil industry.