A man steps into a London jewelry store and pulls a gun. He throws a small bag at the clerk and instructs him fill it. The clerk complies and hands back the sack. The man, Patrick Holt, starts for the door just as several coppers put in an appearance.
Holt bolts out the back door with the police in hot pursuit. After a brisk chase, Holt is tackled and cuffed. He is hauled off to jail and a date with the judge. The judge gives him three years for the bungled robbery.
While waiting for the bus to prison, he meets another prisoner, Michael Balfour. Balfour is a member of a high-end warehouse robbery gang going up for a two years bit The two talk as they are transported to the big house.
Several weeks later they are informed of a transfer to another prison. They are cuffed to a pair of guards and loaded on a train. Balfour fakes sickness and the one guard leaves for help. Holt gets the upper hand on his man and knocks him out. Off come the cuffs and a leap from the train starts their escape.
Holt and Balfour steal a car and head off to London. They stop at a small roadside café for coffee and a sandwich. Balfour likes how Holt handled himself and wants him to join the crew he works with. The gang only pulls big scores that earn top money. Robert Ayres, an American Army deserter, is the man in charge.
The pair leaves the café and head for Ayres place. As they go, Holt drops an empty cigarette pack. Another customer grabs the pack and pockets it. The man, Alan Judd, grabs a car to Scotland Yard. He hands the pack to Police Detective Hector Macgregor. We discover that Holt is really a Scotland Yard man sent undercover to get the goods on Ayres.
The jewel robbery etc had all been a set up to get Holt noticed. Balfour introduces Holt to Ayres and vouches for him. He tells Ayres how Holt worked over the prison guard during their escape. One of the gang, Michael Brennan, does not like Holt and starts a fight. Holt levels him with a few lefts ending the discussion. Ayres likes his style and takes him into the gang. He gives the two a room to hide out for a few days till the police chase cools.
Enter Ayres' bit of fluff, Sandra Dorne. The blonde bimbo likes to spread it around and she takes an instant liking to Holt. Balfour tells Holt that she is bad news.
Several days later Ayres sends Holt and Brennan out on a van hi-jacking. The van is full of nylons, worth a fortune in post-war UK. The job goes smooth and by the numbers. The pair deliver the van to one of Ayres fences and head back to the hideout.
Holt hits the local coffee shop to grab cigarettes and passes the fence's address to his waiting contact, Judd. Judd takes the info to the Yard and a raid is launched on the fence's place. The goods and the fence are quickly gobbled up. Brennan blames Holt but Ayres figures Brennan is still upset at the beating Holt gave him. Ayres writes off the lost goods as one of those things. Ayres tells the crew that a real "big' job is coming off in a half hour.
Holt slips out to tell his contact about the job. Brennan, who is really upset with Holt, follows. He spots the hand off and tails Judd. He pulls Judd off the street, sticks a gun in his face and drags Judd into a bombed out ruin. He searches him, finds the note and realizes Holt is really a Cop. Judd tries to escape and is shot by Brennan. Brennan smiles and heads back to the hideout to tell Ayres about Holt.
A further complication for Holt now pops up. Dorne corners him and suggests he double-cross Ayres. The two can live the high life together on the score. Holt is not sure what to make of the offer, but agrees in order to keep Dorne quiet. It is now time to find out what the score is.
The job is a fur coat warehouse. There is an inside man who will let them in at closing. They just need to take care of the watchman and then they have the whole night to load the swag. "Time to go!" Shouts Ayres. "Where is Brennan?" Ayres decides they cannot wait for him and the crew takes off.
Brennan finally gets to Ayres place where Dorne tells him the location of the job. Brennan grabs Dorne's motor and speeds off to catch Ayres.
The warehouse job is going like clockwork and the crew is swiftly loading a large truck with furs. Brennan shows, takes Ayres aside and fills him in on Holt. Ayres tells Brennan to wait till the job is finished, then take Holt into the back and deep six him.
While this is going on, Judd's body has been found and the Yard called. They pile into their cars and raid Ayres' office and pinch Dorne. The Police lean on Dorne who quickly folds after Macgregor says, "It is a murder case so talk! Where is the robbery?" Back into the cars they go and race to the site.
The truck loaded, Brennan sticks a gun in Holt's back and points into the warehouse. Holt gives him a shove and takes off. Brennan gives chase firing off several shots. Ayres pulls his own gun and joins the pursuit as Holt leads them onto the roof. Ayres plugs Brennan in error, but also manages to wing Holt just before the Police put in a last minute showing. The gang is rounded up and Holt gets a ""job well done" before a trip to the hospital. (b/w)