He was adopted by a rich family and despises their biological son and older stepbrother, Baek Sung-Chul.

There, he finds strange symbols carved into every door and meets his brother's neighbor Joo-hee and her young daughter Pyeong-Hwa.

Sung-soo later figures out that the symbols on the doors are "hide and seek codes" that indicate the gender and numbers of people.

The police manage to break in and secure the room while Sung-Soo cradles Min-Ji's unconscious body and their tearful children yells at her to wake up.

Some time later, Sung-Soo and his family visit his parent and Sung-Chul grave, finally making peace for his brother and free from his guilt before they travel back to America.

As the new residents settle in, the camera turns on the wardrobe in which Pyeong-Hwa still hides, looking at them, narrating the voiceover from the beginning.

A low-budget (₩2.5 billion) thriller with no high-profile director or stars,[6][7] Hide and Seek was an unexpected hit upon its release on August 14, 2013.