After a scientific experiment goes horribly wrong during a demonstration, a scientist finds himself trapped in an alternate reality that bears some similarities to our own, but also has some striking differences. In this other reality the Second World War had never occurred, mankind had not yet traveled into Space and Mt. Everest had not yet been conquered, just to name a few things. Also in this other reality he is no longer a scientist but rather a well known author. After a personal tragedy in this alternate world, he finds himself back in his own world and desperately trying to locate the woman he fell in love with in the other world. Little does she know, however, that her life depends on him finding her.
The story of British serial killer John Christie, who committed most or all of his crimes in the titular terraced house, and the miscarriage of justice involving Timothy Evans.
A small boy, Dickie Goodwin, finds some strychnine pills mixed with sweets in a stolen car left in a deserted garage. With them he buys his way into the Rocket Gang. Brian, the leader, shares out the pills for swaps next day. One of the gang eats hers and collapses. The police frantically search for the pills and a broadcast appeal is made. Brian hears this and reaches the gang at Battersea funfair just in time to save them.
A vicious gang of crooks plan to steal the wages of a local factory, but their carefully laid plans go wrong, when the factory employs an armoured van to carry the cash. The gang still go ahead with the robbery, but when the driver of the armoured van is killed in the raid, his wife plans revenge, and with the police closing in, the gang start to turn on each other.
A renowned safecracker and his crew try to rob a bank by entering the vault through the sewer system.
In Tiger Bay, the docklands of Cardiff, rough-and-tumble street urchin Gillie witnesses the brutal killing of a young woman at the hands of visiting Polish sailor Korchinsky. Instead of reporting the crime to the authorities, Gillie merely pockets a prize for herself — Korchinsky's shiny black revolver — and flees the scene. When Detective Graham discovers that Gillie has the murder weapon, the fiery young girl weaves a web of lies to throw him off course.
Scotland Yard detectives attempt to solve a spate of safe robberies across England beginning with clues found at the latest burglary in London. The film is notable for using a police procedural style made popular by Ealing in their 1950 film The Blue Lamp. It is known in the US as The Third Key.