South Korean actors Kang-Ho Song and Do-Yeon Jeon with director Lee Chang-Dong
© AFP Christine PoujoulatCANNES, France (AFP) - The melodrama ("Milyang" in Korean), which joins 21 other films in the running for the Palme d'Or, is Lee's first picture in four years.
Gifted lead actress Jeon Do-yeon portrays Shin-ae, a piano teacher who moves with her son to the hometown of her late husband, whose death is still the source of unbearable pain.
She dotes on her young son as a link to his father and as the only family she has left. Their affection and reliance on each other are palpable.
When, in a cruel and unexpected twist in the story, he is abducted and killed, Shin-ae turns to evangelical Christianity on the advice of her pharmacist, a devout believer, as a means of dealing with her grief.
Filled with religious fervor, she decides to visit her son's murderer in prison to tell him she has forgiven him.
But she is horrified when the killer tells her with a serene smile that he has repented and God has already offered him absolution.
"Who is God to forgive him before I have?" she asks her Christian friends in a rage.
The 53-year-old Lee, a former culture minister and one of South Korea's most sought-after filmmakers, said he was fascinated by the idea of a crisis of faith brought on by tragedy.
"What I wanted to show is how one can overcome pain and grief and find hope again," he said. "The meaning of life isn't to be found in the skies it is really on earth and that is the feeling I wanted to portray."
His 2002 film "Oasis" about a man who falls for a seriously disabled woman, won two key awards at the Venice film festival.
"Secret Sunshine" is one of two South Korean contenders at Cannes, which wraps up Sunday.
Festival favourite Kim Ki-duk presented "Breath," starring Taiwanese actor Chang Chen as a man on death row who falls in love with a scorned wife.
©AFP