De Britse wiskundige Sebastian werkt voor de Britse overheid aan het ontcijferen van vijandelijke codes. Hij wordt verliefd op zijn collega Rebecca Howard, maar als zij hem na een tijdje verlaat, ziet Sebastian zijn werk niet meer zitten.
Nee, helaas is Sebastian nog niet beschikbaar op Netflix in Nederland.
| Directing | David Greene | Director |
| Production | Herbert Brodkin | Producer |
| Writing | Gerald Vaughan-Hughes | Screenplay |
| Production | Michael Powell | Producer |
| Editing | Brian Smedley-Aston | Editor |
| Production | Gerry Fisher | Producer |
| Camera | Gerry Fisher | Director of Photography |
| Sound | Jerry Goldsmith | Original Music Composer |
| Writing | Leo Marks | Story |
| Production | John Pellatt | Associate Producer |
| Production | Edith Hamlin | Casting |
| Art | Wilfred Shingleton | Production Design |
| Art | Fred Carter | Art Direction |
| Art | Terence Morgan | Set Decoration |
| Costume & Make-Up | Bob Lawrance | Makeup Artist |
| Costume & Make-Up | Gladys Leakey | Hairdresser |
| Production | Clifton Brandon | Production Manager |
| Directing | Gordon Gilbert | Assistant Director |
| Art | Terence Morgan II | Set Dresser |
| Art | Alf Pegley | Property Master |
| Sound | H.L. Bird | Sound |
| Sound | Tristram Cary | Sound Effects |
| Sound | Don Challis | Sound Editor |
| Sound | Gerry Humphreys | Sound |
| Camera | Jimmy Turrell | Camera Operator |
| Camera | Wally Byatt | Focus Puller |
| Costume & Make-Up | Bridget Sellers | Wardrobe Master |
| Costume & Make-Up | Sue Yelland | Costume Consultant |
| Editing | Keith Palmer | Assistant Editor |
| Editing | Jimmy Turrell | Assistant Editor |
| Directing | Ann Skinner | Continuity |
| Directing | Zelda Barron | Continuity |
| Art | Richard Williams | Opening Title Sequence |
