The Korean War began 74 years ago this week — and with it, an extended nightmare for the teenager Park Chung-am.

For over two years, Park infiltrated deep into North Korean territory to gather intel, disrupt supply routes and rescue prisoners, facing the constant threat of death as he served in the U.S.-led 8240 Unit.

But despite the dangerous work that Park and fellow agents who hailed from the North carried out in support of the war effort, the secrecy of their missions and lack of military identification has meant that their heroics have gone almost entirely unrecognized — until