Hugh Boneville and Janet McTeer star in this gripping two part crime thriller. When extremists kidnap two 7yr old boys from very different backgrounds, and promise to release them only if their radical demands are met, the pragmatic Detective Superintendent Iain Barclay and faithful deputy, Detective Sergeant Amy Foster are on the case. Emails arrive at Barclay's office, with images attached of the two boys seemingly unconscious, the word 'sacred' written on their bodies and a series of demands that the police team simply cannot meet.