Experienced New York Police Detective John Harris is sent to London to help a local task force investigate a series of gangster killings organized by a new player in town, an American. With the help of a young teen wronged by gangsters, Harris navigates London's seedy, drug-fuelled underworld in order to take down its new criminal empire.

Expert safecracker Arthur Clutten masterminds heists for a criminal syndicate he belongs to. But after witnessing the brutal methods of persuasion being meted out by gang leader, Ignatius Smith Clutten decides to quit. But he realizes the gang would sooner see him killed than quitting. After stealing some documents incriminating Smith and his boss, Edward Ross, Clutten then puts his family in hiding and goes on the run...but his daughter has been kidnapped by the gang and a hitman has been hired and is close to finding Clutten.

The everyday lives of working-class residents of Albert Square, a traditional Victorian square of terrace houses surrounding a park in the East End of London's Walford borough.