Sehim's field trip to Banhyang Island takes an ominous turn when a fierce storm leaves everyone stranded. As three students inexplicably vanish amidst the storm, Sehim and his friends scramble to find out why. But, their desperate efforts only seem to drag them deeper into the island's sinister secrets— every revelation intensifying the chilling forces lurking on the island, their chances of leaving the island seem uncertain by the day.