
A brilliant but undisciplined mathematics prodigy works in the British Intelligence “cipher bureau,” where he relentlessly cracks enemy codes. Amid the high‑stakes world of espionage, he also pursues a romance with his colleague Rebecca Howard, balancing his talent for decryption with a growing love.
Does Sebastian have end credit scenes?
No!
Sebastian does not have end credit scenes. You can leave when the credits roll.
Explore the complete cast of Sebastian, including both lead and supporting actors. Learn who plays each character, discover their past roles and achievements, and find out what makes this ensemble cast stand out in the world of film and television.

John Gielgud
Head of Intelligence

Donald Sutherland
Ackerman

Lilli Palmer
Elsa Shahn

Margaret Johnston
Miss Elliott

Nigel Davenport
Gen. Phillips

Susannah York
Rebecca Howard

Janet Munro
Carol Fancy

Dirk Bogarde
Sebastian

Ann Beach
Pamela

Veronica Clifford
Ginny

Ronald Fraser
Toby

James Belchamber
Man with Dog

Ann Sidney
Naomi

Hayward Morse
Gavin

Charles Farrell
Taxi Driver

John Ronane
Jameson

Jeanne Roland
Randy

Charles Lloyd Pack
Chess Player

Sally Douglas
Uncredited

Portland Mason
'UG' Girl

Louise Purnell
Thelma

Alan Freeman
TV Disc Jockey

Lynn Pinkney
Joan

Susan Whitman
Tilly

Stuart Hoyle
Uncredited
Discover where to watch Sebastian online, including streaming platforms, rental options, and official sources. Compare reviews, ratings, and in-depth movie information across sites like IMDb, TMDb, Wikipedia or Letterboxd.
Challenge your knowledge of Sebastian with this fun and interactive movie quiz. Test yourself on key plot points, iconic characters, hidden details, and memorable moments to see how well you really know the film.
Which actress portrays the model and former mathematics student Rebecca Howard?
Susannah York
Lilli Palmer
Janet Munro
Julie Christie
Show hint
Read the complete plot summary of Sebastian, including all major events, twists, and the full ending explained in detail. Explore key characters, themes, hidden meanings, and everything you need to understand the story from beginning to end.
On the busy streets of Oxford, Rebecca Howard, Susannah York, a model and former Oxford mathematics student, is sprinting to attend the ceremony where the Prime Minister is to be awarded an honorary degree when she collides with the aloof Sebastian, Dirk Bogarde. After a sharp insult, Becky is strangely intrigued by him and follows him to the ceremony.
Back at the event, Becky proves resilient and quick-witted, spelling her own name backwards during a particularly tough interview, and Sebastian hands her a phone number inviting her to call if she wants an unspecified job with the British civil service.
Becky soon learns that the position is with the all-female decoding office of British Intelligence that Sebastian directs, a unit dedicated to deciphering codes used by secret agents and foreign spies. As she settles into this demanding new role, she becomes captivated by the enigmatic director, whose private life remains a guarded mystery.
Within the hierarchy, Gen. Phillips, head of security, grows suspicious of Elsa Shahn, a longtime senior decoder with left-wing leanings. Elsa Shahn, Lilli Palmer, is seen as a potential security risk, but Sebastian argues for retaining her because of the crucial value she provides to the operation. Becky, observing the tension, becomes entangled in the office dynamics and the personal allure surrounding the director.
Becky moves closer to Sebastian, and their professional relationship blooms into romance, even as he leaves his girlfriend, Carol Fancy, Janet Munro, a faded pop singer who carries her own burdens and ambitions. The era’s swinging mood shades the workplace as Becky grows frustrated with Sebastian’s single‑minded devotion to his work, which strains their relationship and his living situation.
The plot thickens as Shahn’s political ties come under scrutiny, and a security breach emerges to threaten the entire operation. When Phillips confronts the issue and Becky accidentally reveals their relationship to the office, Sebastian resigns, ends things with Becky, and returns to Oxford, leaving the decoding team to pick up the pieces. Months pass, and the Head of Intelligence asks Sebastian to come back temporarily because the Americans want his help deciphering signals from a Russian spy satellite, a request he agrees to only if Shahn can receive a full pension.
In the pursuit of Becky, who has also stepped away from the decoding department, Sebastian encounters Carol at her apartment. He is drugged with LSD and lured to the top of the building by Toby, Ronald Fraser, who is secretly a foreign agent and Carol’s lover. Just as Toby engineers a deadly ploy to push Sebastian toward a fatal leap, General Phillips intervenes, saving him and arresting Toby.
Sebastian finally locates Becky, and the truth comes to light: he is the father of her newborn baby, and his love for her remains. A clue to the Soviet signal emerges from the sound of the baby’s rattle, and Becky helps Sebastian pivot to decoding the signal in her own living room, bridging love, duty, and ingenuity in a tense, clever finale.
Uncover the Details: Timeline, Characters, Themes, and Beyond!

Coming soon on iOS and Android
From blockbusters to hidden gems — dive into movie stories anytime, anywhere. Save your favorites, discover plots faster, and never miss a twist again.
Sign up to be the first to know when we launch. Your email stays private — always.
Immerse yourself in the magic of cinema with live orchestral performances of your favorite film scores. From sweeping Hollywood blockbusters and animated classics to epic fantasy soundtracks, our curated listings connect you to upcoming film music events worldwide.
Explore concert film screenings paired with full orchestra concerts, read detailed event information, and secure your tickets for unforgettable evenings celebrating legendary composers like John Williams, Hans Zimmer, and more.
Explore all cars featured in Sebastian, including their makes, models, scenes they appear in, and their significance to the plot. A must-read for car enthusiasts and movie buffs alike.
Discover the central themes, ideas, and keywords that define the movie’s story, tone, and message. Analyze the film’s deeper meanings, genre influences, and recurring concepts.
Explore the various alternative titles, translations, and other names used for Sebastian across different regions and languages. Understand how the film is marketed and recognized worldwide.
Browse a curated list of movies similar in genre, tone, characters, or story structure. Discover new titles like the one you're watching, perfect for fans of related plots, vibes, or cinematic styles.
What's After the Movie?
Not sure whether to stay after the credits? Find out!
Explore Our Movie Platform
New Movie Releases (2026)
Famous Movie Actors
Top Film Production Studios
Movie Plot Summaries & Endings
Major Movie Awards & Winners
Best Concert Films & Music Documentaries
Movie Collections and Curated Lists
© 2026 What's After the Movie. All rights reserved.