Sung-soo is a successful businessman who lives with his wife Min-ji and their children in a luxury apartment. Life is mostly good, except for an older brother from whom he's estranged.

One day, Sung-soo receives a phone call that his brother is missing and goes to his brother's apartment building for the first time in decades to look for him. There, he finds strange symbols carved into every door and meets Joo-hee and her young daughter. Joo-hee is convinced that someone is spying on them and lives in constant fear.

Sung-soo figures out that the symbols carved onto the doors are "hide and seek codes" that indicate gender and number of people. Then when he returns home, he finds similar symbols carved into his door.

Hide and Seek (Hangul: 숨바꼭질; RR: Sumbakkokjil) is a 2013 South Korean mystery film written and directed by Huh Jung in his feature directorial debut. It revolves around two families who believe strangers to be living in hiding in their homes, and struggle to fight back.