一宗離奇滅門血案，死者全遭鐵錘狠狠打死，偵探查案緝兇到連環殺手疑犯的公司，誓要把潛藏的惡魔揪出來；表面上他與常人沒有分別，內裡卻冷酷無情，被欺負的女實習生竟然日日朝九晚九與魔鬼同行!辦公室內外形同密室，與今日的韓國一樣，在經濟和工作壓力相逼之下，令打工仔求生不得，求死卻萬萬不能!新導演洪元燦絕非影壇初哥，擅長處理高度精密的驚悚黑暗題材，參與編劇的作品包括《追擊者》、《股神戰場》、《我是殺人犯》等，部部皆是水準之作，今次以幽閉的辦公室空間拍出緊張詭異的氛圍，聯同高雅星、朴誠雄、裴成佑、金義城、裴成宇殺入康城午夜場。

One night, ordinary white-collar worker Mr. Kim (Bae Seong-woo) goes home and murders his whole family. With Mr. Kim still on the loose, his office colleagues – who have not exactly treated him kindly over the years – are now looking over their shoulders in fear. The sole exception is Mi-rae (Ko Ah-sung), the lowly bullied intern who was the only person that showed Mr. Kim a trace of kindness. The chilling directorial debut of THE CHASER scriptwriter Hong Won-chan may have a serial killer as its boogeyman, but it’s the pressure cooker environment, uncaring management and subtle bullying that make the cutthroat world of the office the deadliest weapon of all.