On 21 January 1968, 31 North Korean commandos of Unit 124 are shown to have infiltrated South Korea in a failed mission to assassinate President Park Chung Hee.

As a means of retaliation, the Republic of Korea Armed Forces assembled a team of 31 social outcasts including criminals on death row and life imprisonment, in a plot to kill Kim Il Sung.

The apprehended soldier is then returned to the camp, tied up, and made to watch his fellow Unit 684 members being beaten by the guards for the two men's betrayal.

Torn between his duty to follow orders and his personal honor, the commander intentionally leaks this information to one of the Unit 684 members.

An official pronouncement is heard over the radio that 20 "armed communist agents" have infiltrated the country, and a state of emergency is declared.

After charging through one army roadblock and winning a firefight they are eventually stopped and surrounded by soldiers in front of the Yuhan Corporation building in Dongjak District, Seoul.

A firefight ensues, with the Republic of Korea Army showing no regard for the welfare of the civilians on board the bus.

To avoid further bloodshed, the surviving Unit 684 members release the civilian hostages, before committing suicide using their own hand grenades.

[5] Brigadier General Nam Dae-yeon said that the 31 Silmido recruits who made up Unit 684 were part of a Republic of Korea Air Force squadron.

One of the guards, Yang Dong Su, confirmed that the unit's mission had been to infiltrate North Korea and kill Kim Il Sung.

[6]On May 19, 2010, the Seoul Central District Court ordered that the government pay 273 million won in compensation to the families of 21 members of Unit 684.