Correction (July 7, 2021 at 9:34 a.m. KST): This article has been updated to reflect Park Jong-lin's recollections in the book "Unchangeable" on seeing his daughter during the 2007 family reunion event.

On his third decade of toiling away in South Korean prison, Park Jong-lin wrote a pained letter about his long-lost daughter, Okhee, who he only got to raise for four months before being deployed on a spy mission to Seoul that changed his life forever.