This movie was quite simply one of the biggest mindf**ks I've ever witnessed.

I couldn't think of anything bad with this one. It's true. perfect from start to end. It's a dark end but it's perfect.

Two brothers start living in a new house, in a completely new neighborhood with their parents and the movie begins with the young brother Jin Seok played by Kang Ha neul, talking about their family, especially his hyung Yoo Seok (played by Kim Mu-yeol) who happens to be the kind of person who never smokes, never drinks, and is all around intelligent, kind, and friendly despite getting into a serious accident and gaining a limp in his leg.

We see how truly enamored Jin Seok is with his family and most of all his hyung who he treats like a god. We also see that Jin Seok not only suffers from terrible nightmares but also takes anxiety medication. It is unclear why he needs it, that part is not explained.

There's a room in their new home which the previous owner had instructed them not to use so the brothers have to sleep in the same room. When Jin Seok questions his father about the room his father explains that the owner left clear instructions: never to go inside that room or touch anything in it.

That night, Jin Seok hears noises coming from the room but no one else in the house seems to hear anything so Jin Seok attributes it to the thunderstorm.

But the room and strange occurances still continue to haunt Jin Seok.

When Yoo Seok sees his brother is still feeling a bit anxious, he takes him outside in the rain for fresh air hoping it would make him feel better. The brothers both take in their new surroundings. It's obvious how much they love each other. How protective they are of each other, enjoying junk food together and constantly teasing. They don't even mind sharing the room so much.

When his hyung gets a call from his father, on his phone to bring him a document that he needs to study, Yoo Seok tells his younger brother to wait for him and he will be right back.

But before Yoo Seok has even returned to his house, some men beat him up and push him inside a black van while Jin Seok tries madly to go after them and manages to memorize the license plate number of the van before he collapses.

When he wakes up, there's no news of his brother still, no one can find him. They wait and wait for the kidnappers to call and demand ransom but nothing happens for ten days.

On the tenth day, Yoo Seok walks inside his home, looking unharmed but he can't seem to remember anything about what went on during those ten days. Everyone assumes it's some kind of amnesia brought about by whatever might have happened while he was gone .

The family is happy to have the son back, they start getting back into their daily routine.

But the more Jin Seok hangs around his hyung, the more he realizes his brother is acting strange. Almost like a different person. At first, Jin Seok shrugs it off as his imagination but things start to get stranger still and many times he wakes up in the middle of the night to find Yoo Seok gone and nowhere to be found.

When he confronts Yoo Seok, Yoo Seok denies it completely and Jin Seok believes him.

Until one night, he follows Yoo Seok.

Honestly, Haneul is the perfect casting for this role because he has this innate innocence that this character carries and his acting from start to finish was just amazing. Best mind games movie I've seen in a very long time.