Sebastian is an undisciplined mathematics genius who works in the "cipher bureau" of the British Intelligence. While cracking enemy codes, Sebastian finds time to romance co-worker Rebecca Howard.
Sebastian is a 1968 British spy film directed by David Greene, produced by Michael Powell, Herbert Brodkin and Gerry Fisher, and distributed by Paramount Pictures. The film is based on a story by Leo Marks, and Gerald Vaughan-Hughes wrote the screenplay.