After being available only in poor-quality prints for decades, the film was released in high quality by French media company Canal+ in 2005.
Detective Barton is searching for a necklace stolen by a gang of thieves. In the beginning, the gang is in a house in London, before going on the run.
The film starts off with Detective Barton (John Stuart) arriving at a house marked for sale or rent. The door is unlocked and he wanders in. An unknown person with a candle is wandering about and a dead body is found. When confronted the mysterious person claims innocence of the murdered person. Barton (who introduces himself as Forsythe) asks the stranger what he has in his pockets (handkerchief, string, sausage, picture of a child, half a cigarette), before the shadow of a hand is shown reaching for a doorknob. The stranger (who later introduces himself as Ben) searches the body of the dead person and finds handcuffs and a gun which he takes.
The detective returns from investigating the weird sound and finds the handcuffs which the stranger left on the ground. A person is seen to be crawling on the roof through shadows, who then falls through the roof. This is a woman called Miss Ackroyd (Ann Casson) who is revived and cries out for her father. She explains that her father went onto the roof and that they are next door in number 15.
The bell tolls half past midnight and the dead body has disappeared. Three people arrive at the windswept house, Mr. Ackroyd (Henry Caine), Nora (Anne Grey) (who is deaf and dumb) and a third person. Ben draws out the gun. Ben accidentally shoots the governor. Mr. Ackroyd draws out a gun and asks him to search the gentlemen, Ben and Miss Ackroyd. The telegram is revealed to Mr. Ackroyd. Sheldrake (Garry Marsh) gets the diamond necklace, which he has hidden in the upper portion of a toilet. Ben causes a commotion and is locked away with Sheldrake.
The two hands of Sheldrake reach out and appear to strangle Ben who is only pretending to be knocked out. More members of the gang arrive. They suggest tying up Miss Ackroyd and 'Forsythe'. The three thieves all have to catch a train. However, one of the "thieves" is Miss Ackroyd's father—a police officer—who locks away two of the thieves and frees Miss Ackroyd and Doyle. He opens the door where Ben is locked away with Sheldrake and gets into a fist fight with Sheldrake.
The other man reveals himself as Sheldrake (the supposed 'corpse' from earlier) and frees the others. Miss Ackroyd and 'Forsythe' are tied up again. Nora reveals herself to be able to speak and says "I'm coming back". She comes back and frees Miss Ackroyd and Doyle. Miss Ackroyd faints but recovers. Nora returns to the basement to allay the suspicions of the other thieves and buy time for the rest to get away. They free Ben and Miss Ackroyd's father. The thieves arrive at the train yard, and board a freight train that is departing. The train says Deutsch-Englischer Fahrverkehr Ferry Service between Germany-Great Britain.
The train departs with Ben aboard and he stumbles onto crates of wine. The thieves, after dispatching the conductor, go to the front of the train, shoot the fireman, and catch the Driver as he faints. 'Forsythe' failed to get on the train before it departed and commandeers a bus. Ben is revealed to have the necklace. Sheldrake discovers he doesn't have the diamond and the thieves fight each other. Sheldrake claims that 'Barton' a detective posing as a thief. A chase scene occurs on the train as the thieves go after Barton. Barton escapes and handcuffs Nora. The bus that 'Forsythe' is on races after the train. The thieves, realising the train is accelerating, try to find the brakes. They turn dials helplessly and notice the bus that 'Forsythe' is on.
Pushing levers and turning dials does nothing, indeed, it only makes the train go faster, leaving the thieves unable to escape. At the dock, the ferry pulls up. As 'Forsythe' watches, the train hurtles through the dock, crashes into the train currently on the ferry at full speed, and pushes it out to sea, dragging the remaining cars into the ocean. People are rescued from the water. Henry Doyle tells Forsythe that he is posing as Detective Barton. But Forsythe is actually Detective Barton, who says to Doyle, "You can't be Barton because I am." All of the thieves are apprehended by the police who are on the scene. Nora asks Barton, "What are you going to do about it?" Barton replied "You better come along with me." Nora says "Where?" "To breakfast." Barton says, and they laugh. Ben then reveals he has the diamond necklace.Leon M. Lion as Ben
Anne Grey as Nora – The 'Deaf-Mute' Girl
John Stuart as Barton – The Detective
Donald Calthrop as Brant – Nora's Escort
Barry Jones as Henry Doyle
Ann Casson as Rose Ackroyd
Henry Caine as Mr. Ackroyd
Garry Marsh as Sheldrake
Hitchcock returned to England from a trip to the Caribbean with a new idea for a film. He told John Maxwell about it, but Maxwell said that Walter C. Mycroft had a different film for him to do, a filmed version of Joseph Farjeon's play Number Seventeen. Hitchcock was unhappy with this, as he considered the story to be too full of cliches and he wanted to do a version of John Van Druten's London Wall. The director who eventually got to do London Wall at the time, wanted to direct Number Seventeen.
Hitchcock was assigned writer Rodney Ackland for the film, and decided to make the film as a comedy-oriented thriller.
The film makes extensive use of miniature sets, including a model train, bus, and ferry.
Though the opening credits confirm the picture's title is Number Seventeen, much of the promotional material (as per graphic above) and many databases refer to Number 17.
In the book Hitchcock/Truffaut (Simon and Schuster, 1967), Hitchcock called the film "A disaster".
On its initial release, audiences reacted to Number Seventeen with confusion and disappointment. The film is not often revived, but continues with generally negative reviews with critics from Rotten Tomatoes noting the film as, "highly entertaining but practically incomprehensible" and as an "unsatisfactory early tongue-in-cheek comedy/suspense yarn". In the Hitchcock/Truffaut book (see above), François Truffaut has a similar verdict, telling Hitchcock he had found the film "quite funny, but the story was rather confusing".