Mother Leaves Her 5-13 year ood Daughter For Her son That passed away years ago

The movie starts out with A driving car showing a somen and a male, i dont remember if they Hit a dog or if the dog was in the car but that happened and they found a cave covered in wood when they looked in A Girl In Bruises was there i dont really remember but i know the man was drunk, by the way Its in Korean. And the whoel plot is That a Mom Leaves Her 5-10 year okd daughter For A son that passed away and In the start of the movie she finds A girl that will kead her to the trap of “Finding” her son. its in a cave in the backyard of the house