Haunted ex-cop Woo Young-min, now head of security at his uncle's soon-to-reopen department store, is still reeling from a fatal misfire that cost his partner's life. When staff begin dying in front of mirrors-one slitting her throat with a pizza cutter, another skewered by his own pen-Woo's routine job morphs into an investigation the company would rather smother. Scraps of CCTV, half-erased fire records and the mute presence of a twin sister guide him toward an unsettling truth: the blaze that gutted the store a year earlier opened more than drywall. Every reflective surface has become a doorway through which repressed rage and guilt now stalk the living.
Kim Seong-ho stages this discovery with icy precision. Polished concourses, mannequin aisles and stark offices feel clinically safe until the camera tilts to reveal a reflection that blinks out of sync. The film's chatty procedural middle can drag, but the gleaming visual design keeps tension humming, and the late-game perspective flip-when Woo realises which side of the glass he occupies-lands like a gut punch.
Beneath the ghost-story skin lies an autopsy of fractured identity: Woo's mirrored double is the shard of self he tried to bury, the piece that still wields a gun without hesitation. That personal split mirrors the mall's corporate façade; management has plastered over deaths and debts, yet the mirrors preserve every sin until payback bleeds through. Kim pushes this fatalism to the audience by making us scan each pane for something "off." Simply looking becomes a trap, and once the glass decides you've seen too much, it can rearrange reality without warning.
When the credits roll, the question lingers uncomfortably: after staring long enough into the mirror, can any of us be sure which side we're on?
