From NetFlix:
Journalist Catherine Heathcote (Juliet Stevenson) solicits the help of investigator George Bennett (Lee Ingleby) for her documentary about the 1963 disappearance of a 13-year-old girl. But when Bennett abruptly stops cooperating, Heathcote begins to unravel some surprising truths. Now Heathcote may have to reevaluate her deep-rooted beliefs about justice. Based on the book by Val McDermid, this “Masterpiece” special co-stars Greg Wise.
2016 ADDENDUM: You can now stream this two-part film from Amazon Prime. You may be shocked when part one abruptly ends and shows screen credits. Just sit tight, because part two begins immediately after that.
Given the combination of BBC Masterpiece Contemporary and Juliet Stevenson you cannot go wrong with this intriguing, well-written, well-acted mystery. All the episodes are on the disk you get from NetFlix, comprising about 2.5 hours.
Never once did I suspect the truth of what really happened. Indeed the surprise ending really caught me off guard. You will have to decide about the moral ambiguity of the ending.
But I guarantee you, you will not be bored.