After a drunken night on the town, an ordinary Seoul businessman, OH Dae-su, wakes up in the morning to discover he has been locked up without explanation in a mysterious prison. After fifteen years, Dae-su suddenly and inexplicably finds himself freed. A voice on a cellphone taunts him into discovering who kept him imprisoned. Dae-su plunges into a world of competing vengeance, his own drive for revenge matched by the equally implacable and Byzantine...

In the Wo Shing Triad, the oldest gang in Hong Kong, the senior members elect a younger boss as their chairman every two years. This time, lines are divided and war starts when the voting doesn't go how it should.