This action-adventure/spy-drama returns for its sixth season tonight after a two-year break. Don't worry if you haven't seen it before though, as there are new characters and a new enemy so all you need to know is that this lot are in a secretive branch of the British Defence Intelligence service called Section 20 and operate high-risk missions throughout the globe. Sergeant ‘Mac’ McAllister (Warren Brown) leads the new unit (Daniel MacPherson, Alin Sumarwata and Roxanne McKee) as they hunt for a missing terrorist while uncovering a shedload of criminal activity along the way.