Former policeman Wu Yeong Min is emotionally crippled by the memory of a botched hostage situation, which ended his career and killed his partner. Withdrawn and filled with self-loathing, he now works as a security guard in a department store that is set to reopen after a fire. After a spate of gruesome and suspicious suicides in the store, Yeong Min is obliged to investigate out of a sense of duty to his uncle, the store's chairman. While the police, led by a resentful former colleague, begins to suspect the work of a serial killer, Yeong Min investigates a less logical route of inquiry after apprehending a trespasser who believes her twin sister is responsible, despite having perished in the store blaze. (Source: MyDramaList)