As fears of terrorism turn Britain of the near future into a high-tech police state, a mathematical genius returns home for the funeral of his brother, an aid worker killed in Afghanistan. Asked to work on a government surveillance database, he becomes romantically involved with his brother's widow and soon is caught in a far-reaching conspiracy. Suspenseful miniseries stars Benedict Cumberbatch, Anamaria Marinca, Eva Burthistle, and Robert Carlyle. 5 1/3 hrs. total on two discs. Soundtrack: English.