Lesser of Two Evils

The Grid is taken by immense surprise when a known Irish splinter group leader, Patrick McCann (Lorcan Cranitch), walks into a safe house armed with a grenade and demands to talk to someone about Asabiyah. He has crucial information on the Middle-Eastern terrorist group and will only talk to someone high-ranking, who has prior knowledge of its existence. Tom offers to meet McCann, but Harry is deeply suspicious. They meet in a field, and McCann reveals that Asabiyah is planning to hit a British nuclear power station. The climax of the episode brings extreme risk to a long-time member of MI-5, to Tom and to his adopted family.