Adapted from a sensational real-life case in 2013, the intricate story begins when a young man partners with his friend to murder and dismember his parents. Pleading not guilty, the defense attorneys soon turn on each other, as the defendants play the devil and idiot game. Meanwhile, heated debates emerge inside the jury room, where nine jurors grapple with the truth.

In 1985, Cheung Yau-ming was one of five miscreants involved in the brutal murder of a white couple. As he was still a juvenile, the court ordered that he be "detained at Her Majesty's pleasure," a clause in British law allowing the government to imprison young offenders for an indefinite period. The film picks up in 1997, with Yau-ming (now 28) being paid a visit by a girl named Cheung Yue-ling. With only six months to go before the Handover, Yau-ming and 22 other prisoners hope to have their sentences determined soon, fearing what might happen should the decision about what to do with them become the province of incoming Chief Executive Tung Chee-hwa.