DCI Alan Craven is accused of taking bribes. Things go from bad to worse as an internal investigation uncovers a questionable deposit in his bank account. Suspended from duty, Craven must clear his name or face criminal charges.
Tensions mount as Craven and Haggerty are on a stakeout. Haggerty believes Craven is hunting for a dead suspect while Craven sees his new colleague as the source of bitter setbacks in his career and life.
Craven busts a fraudster for carrying an unlicensed firearm and forged passport. But while his fellow officers question his holding the cooperative suspect without charges, the detective increases the pressure to get the information he's really seeking.
Haggerty's father is beaten into a coma in the latest of a series of attacks on travelers. At first the case falls outside of Special Branch's jurisdiction, but when sensitive government documents are stolen from the next victim, the team launch a manhunt
Special Branch officers North and Craven are asked to protect a former Nazi collaborator. Although they have contempt for the man and their assignment, they must shield him from those who remember his old war crimes.
A group of London youths are linked to several deadly bombing attempts. With connections to the IRA, the Communist Party and anarchist elements, the group continues their plot, while the Special Branch works with an explosives-disposal expert to stop them
A junior defense minister's missing husband turns up dead. Highly placed people push for immediate investigation of the case, as growing evidence indicates a suspicious cause of death. Special Branch must learn if it was an accident, suicide, or murder.
When a psychotic ex-CID officer barricades himself and a hostage in an office building, lacing it with multiple bombs, Craven and the Special Branch team are called in. Time ticks down as negotiation fails and the man threatens to set off the detonator.
An outspoken Hollywood actress born in the U.K. comes to star in a London play. Acting on a warning from the FBI, the Special Branch officers attempt to protect her from a highly credible murder threat by a group of right-wing extremists.
A physician is under surveillance as a possible security risk. Despite accusations of the doctor leaking politically sensitive trade secrets from a former Special Branch officer's business, Craven grows increasingly uncertain that the man is a traitor.
A German diplomat's daughter is kidnapped by a Middle Eastern terrorist group. Craven and Haggerty must rescue her before she is killed. But time works against the detectives, and events build to an explosive conclusion.
A South African diplomat visits London, and the men of Special Branch are assigned to protect him from an anticipated assassination attempt. But DCI Craven worries about Sgt. North's effectiveness and doesn't find the diplomat's attitude helpful.