Communication is the key to the survival for nine strangers who have been kidnapped by a masked gunman and told that one of them will die every ten minutes until they discover how they are all connected. Who of the nine lives and who dies?

Police ambush and kill several gang members in Los Angeles. Gang members make a pact of blood to strike back at police, and conduct a siege on the police station which is almost abandoned and due to be closed. Staff of the closing precinct and the criminals being held there while in transit must work together to fight off the attacking gang members.

In England, retired marine Harry Brown spends his lonely life between the hospital, where his beloved wife Kath is terminally ill, and playing chess with his only friend Leonard Attwell in the Barge pub owned by Sid Rourke. After the death of Kath, Len tells his grieving friend that the local gang is harassing him and he is carrying an old bayonet for self-defense; the widower suggests him to go to the police. When Len is beaten, then stabbed to death in an underground passage, Inspector Alice Frampton and her partner Sergeant Terry Hicock are sent to investigate. They pay Harry a visit but don't have good news; the police have not found any other evidence, other than the bayonet, in order to arrest the hoodlums. This mean that should the case go to trial the gang would claim self-defense. Harry Brown sees that justice will not be granted and decides to take matters into his own hands.