Ex-gangster Sonny Koo finds himself in the middle of a bank holdup by two inexperienced crooks. The robbery goes awry, but before order can be restored, Sonny assumes control. He proceeds to turn the hostage situation to his advantage, and uses the bank's customers and personnel as leverage to free his girlfriend from prison. On the outside, sympathetic cop Ah Sai debates with his captain over how to handle the situation.