A Haunted Den (Korean Folk Village) Koreans have long held that a good fright is the cheapest air conditioner. This summer, theme parks and film sets across the country are testing that theory with immersive horror programs that put visitors inside the story.Korean Folk Village in YonginThe folk village in Yongin, Gyeonggi Province, runs two horror attractions."A Haunted Den" lasts roughly five minutes. Visitors enter in groups of four through what looks like an abandoned hanok, so dark that staff hand out a flashlight at the entrance. The lead visitor carries the light while the others follow in single file with their hands on the shoulders of the person in front of them. A maiden ghost in white robes with long hair appears from behind and follows. A corpse rises and moves. Performers in Joseon-era dress work the space from the front, sides and back without pause, and each room must be cleared in full before the next door opens. There is no exit in the middle.The attraction operates Fridays, Saturdays, Sundays and national holidays from 1 p.m. to 9 p.m. Admission is limited to ages 13 and older, and costs 11,000 won per person."A Haunted Prison" is billed as the longest outdoor horror course in Korea. The premise: Sindanggol, a village seized by the shaman Ihwa, has decayed into a ruin overrun by malevolent spirits. A royal party vanished at the village pass, and every investigator sent after them vanished too. Visitors take the role of exorcists tasked with finding out what happened and surviving the spirits' lair. Nine to 10 ghost performers appear across the course.The attraction operates Fridays, Saturdays, Sundays and national holidays from 1:30 p.m. to 9:30 p.m. Admission is limited to ages 13 and older, and costs 16,000 won. Because the course is outdoors, going after sunset is the way to get the full effect.From Aug. 1 through Sept. 6, the Korean Folk Village extends the theme site-wide, with ghosts roaming the grounds for a festival of the dead. For anyone curious about horror staged in a Joseon-era setting, this is the place to start. Gwimun-Z Protocol (Lotte World Adventure Busan) Lotte World Adventure in Seoul and BusanLotte World Folk Museum inside Lotte World Adventure Seoul is staging "Stay Alive in Museum," an interactive horror performance in which the museum's entire floor is used as the stage.The story begins during preparations for a special exhibition on the history of Korean curses, when a sealed curse comes loose. Audience members are cast as new recruits on the Lotte World performance team, helping to set up the exhibition until they find themselves trapped inside the museum with a limited window to survive. Individual choices send the story down different paths.The show starts at 7:30 p.m. on weekdays and weekends, with a running time of 90 minutes. Admission is limited to ages 16 and older. Tickets are 50,000 won via the Lotte World website.Lotte World Busan has two new attractions. "Gwimun Radio" delivers its scares through sound rather than sight, telling Busan-set ghost stories. "Gwimun-Z Protocol," which costs an extra 5,000 won, drops participants into a laboratory overrun by zombies, with five minutes to find the clues and escape. Hapcheon Ghost Park Masquerade (Hapcheon Movie Theme Park) Hapcheon Movie Theme ParkKorea's largest period drama, set in Hapcheon, South Gyeongsang Province, turns into a horror festival called "Hapcheon Ghost Park Masquerade" July 31 through Aug. 16. This year's masquerade theme gives visitors the role of masked ghost hunters. Visitors must search the grounds for clues and complete missions to put spirits back to rest.The set reproduces streets from the 1920s through the 1980s, along with the Japanese Government-General of Joseon building, Gyeongseong Station and Cheong Wa Dae. The set has served as a location for various dramas, including "Mr. Sunshine" and "When Life Gives You Tangerines." For the festival, nighttime lighting and 42 performers in special-effects makeup as zombies, vampires and maiden ghosts will be added.The site is divided into four zones, A through D, by the intensity of fright, each with its own mission, psychological games and quizzes to work through. The festival runs daily from 6 p.m. to 11:30 p.m. Weekend admission is 30,000 won for adults, 20,000 won for middle and high school students, and 10,000 won for elementary school students.