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.

• Paramount Pictures
• Paramount British Pictures
• Dirk Bogarde
• Susannah York
• Lilli Palmer
• John Gielgud
• Janet Munro
• Ronald Fraser
• Margaret Johnston
• Nigel Davenport