this question is about korean horror movie called GHOST, i need help please?

Question

i watched the movie twice, and it really confused me.

when i was watchin it first time, i fought the main evil ghost who was killing the girls was the girl i think named Sin or something (the quite girl who gets bullied).

but in end i realise, the evil ghost is actually the girl named Ji woon (the girl who pushes the other girl into the river)

but suddenly i find out that the quite girl's soul (the one who died drowing), is in the Ji woon body (the girl who pushed the quite girl into the river)

in end the quite girl mother looks aggressive, and during the film, JI woon mother is strange, she changes her personality in the end.

please tell me the whole story, who is in who's body and wats going on its confusing me etc.

Answer 1

Ryeong (2004) aka Dead Friend

when Su-in and Ji-won were both in the water,their spirits switched bodies. Su-in's body died,and Ji-won became trapped inside Su-in's dead body,while Su-in went inside Ji-won's body and got her wish to become her and live her life.I'm guessing Ji-Won was stuck inside Su-in's dead body at the bottom of the lake all this time waiting,until the seance at the beginning, which released Ji-won's spirit ( her friends didn't start dying and everything didn't start happening until after Eun-sao's sister did the seance). Ji-won was just waiting for a chance to come and get her body back and get back at the friends who didn't bother to help her when she was drowning.

Ji-won murdered all her friends because to her they were traitors for not helping her in the lake.....they didn't do anything to help. Eun-sao was jealous of Ji-won being the leader of their group and always getting what she wanted. Ji-won knew Eun-sao was jealous of her...... Eun-sao didn't even bother to help Ji-won even though she was standing there watching her drown and Ji-won realized that Eun-sao didn't care if she drowned or not.....maybe even wanted her to drown especially when Ji-won saw Eun-sao smile before she went under the water for the last time......
.Because of this fact....she got real pissed at her friends.
After all if they hadn't of pushed her in (or if Eun-sao had of at least helped her out)she would still be alive and not trapped in someone else's body.

Ji-won is now inside Su-in's mother (Su-in's mother was the one who worked at the fish place always cutting fish,which is why Ji-won always used to tease Su-in about the awful fish smell).She is waiting and hoping for Su-in (who is still inside her body)to come back and visit her there.

Since Ji-won was biting her nails at the end (which Su-in used to do) that Su-in is still inside Ji-won's body.....So Ji-won didn't get her body back.....Su-in is biting her nails because she's scared to go see her mother sensing that Ji-won has possessed her mother....but she's not going to fall for it, and decides to leave for good and travel abroad like she was thinking.
.Ji-won knows that her plan didn't work when she sees Su-in walk away,and knows that she may not be able to get her body back at all,and now she's stuck inside Su-in's mother doomed to a life with old flesh and stinky fish...