Harriet takes up an offer to work for a maverick MP, while Karen Koutoufides uncovers a link between the home explosion and suspicious phone calls between Bailey and the chief of defence.

The US Secretary of Defence arrives in the capital for an unscheduled visit. Garrity seeks a private meeting with drone pilot Cal Treloar.

The dogs of war are circling in the corridors of power, urging a reluctant PM to retaliate against Pakistan. Can Harriet stop the march to war in time?