초대받은 사람들 (1981) / The Invited Ones (Chodaebad-eun salamdeul)

Set during Korea's early Catholic persecutions, the illegitimate son of a high court official falls for a young believer he rescues from arrest, while her father is executed for his faith and his own family climbs the ranks of the government doing the executing. The match their fathers once promised becomes impossible to honour from opposite sides of a crackdown that keeps taking the people around them.

Why it's free: Free on the Korean Film Archive's own channel; the national archive holds the rights to the restorations it publishes.