Hunter (2009)

When extremists kidnap two seven-year-old boys from very different backgrounds, and promise to release them only if their radical demands are met, the case falls into the hands of the intuitive and pragmatic Detective Superintendent Iain Barclay. Faced with a relatively inexperienced and increasingly unreliable team, Barclay calls his friend and faithful deputy, Detective Sergeant Amy Foster, out of "early retirement", and away from the bottle, to support him in solving what turns out to be a highly sensitive crime.

Note: The characters of DSI Iain Barclay and DS Amy Foster are taken from the series "Five Days", created by Gwyneth Hughes.