Pretty interesting idea of a "time travel" movie. Similar vein as The Lake House but it's a thriller instead. There are a few logical flaws which have nothing to do with the time travel segment.
Seoyeon lives in an apartment alone. She hates her mum because as a child she left something cooking on the stove which led to her father dying in the subsequent fire and her leg being scarred by burns. One day she receives a mysterious call of a woman crying for help. As she receives more and more calls she learns more about the woman, Yongsook. Yongsook lives with her abusive stepmother who believes her mental illnesses are actually demonic possession. Seoyeon helps Yongsook feel like she isn't alone and fight back against her stepmother. In exchange, she goes to Seoyeon's house in 1999 and stops the housefire from killing her father. However, when Seoyeon spends all day with her parents and doesn't answer Yongsook's call, things get tense and deadly.
I liked the idea of the story and the two timelines connected. We follow one iteration of the women as the days pass. The story is very singularly focused so we don't learn a lot about the two women's histories. I think the acting was pretty good and the setting interesting and spooky. The house is in a rural village so it is very isolated. What's more is there's a strong sense of community so everyone knows everyone else. Unfortunately, the logical flaws really detracted from the movie.
[spoiler]When the police are investigating the crime, the notebook says that they caught the killer by having evidence handed in. However all signs point to Yongsook as the killer. Her abusive mother went missing, so did the strawberry farmer and she had strawberries in her house. In what universe would the police do nothing about the circumstancial evidence, especially if, at that time, she had her mother's chopped up body parts in the fridge? The other part is the memory thing. Seoyeon doesn't seem to realise things have changed. She only has memories from one timeline. So when her dad is back she doesnt have 20 years of memories with her dad. When she is tortured in the final timeline, she doesn't have cPTSD from being tortured and she doesn't remember her mum surviving or dying in the final confrontation. She doesn't even notice her mum disappearing in the final timeline. Another thing is, in the post-credit scene, we see Yongsook calling herself from the past and warning her. So the phone can call more than 1 iteration of itself now? How do you know? How do you choose the exact time to call? Plus, the phone could never call anyone except itself in the future. So it never calls the police or anything. I felt like these really took away from the story.[/spoiler]
Ultimately it is still a decent movie and definitely worth a watch.