Agent Jo McDonagh works for an elite military group that investigates crimes committed by or against British army members. Her male-dominated unit takes on cases involving murders, espionage, political cover-ups and drug trafficking.
The narrow escape of a sergeant from a mortar accident that cost the life of a lance corporal raises the suspicions of SIB, whose members uncover a link between the men and a war crime. The investigation is complicated, however, by the team's internal chaos.
A harsh, unforgiving sergeant is questioned by SIB after a private dies during an arduous training march, but further investigation reveals a link to illegal boxing matches that involved the victim and his comrades.
The second season opens with Jo in Bosnia pursuing a war criminal. But instead of snaring her man, she discovers the corpses of an ambushed Special Air Services commando team, a grim find that points to a terrorist cell.
An officer's missing BMW, a missing private and a shadowy club owner (Gertan Klauber) are part of an elaborate web of drugs and illegal immigration; Burns encounters an old friend (Tom Mannion) on the verge of being courtmartialed. Lt. Col. Fox: William Scott Masson.