某市市中心的双子大厦，有着姣好面容却冷漠刻薄的房地产销售主管应佳（刘青 饰）边打电话便走进电梯。这时一通电话打了进来，刚刚还是甜美笑容的她在得知对方身份后马上变了一副嘴脸，冷冰冰地回绝了对方。就在此时，电梯突然剧烈颤抖，操作电路板上的数字陷入混乱状态。随着巨大的轰鸣，应佳的电梯直直坠落了下去。原来双子大厦不知因为何故倒塌，一切陷入混乱。当应佳醒来时，发现自己被困在变形的电梯间内，她好不容易找到受损的工作电话，尝试打电话求援。而在求援的过程中，她突然想不起自己究竟是谁。根据接听电话的人提供的线索，她些许拼凑出关于自己的信息。 　　与此同时，废墟附近好像有什么可怕的怪兽在接近……Jia Ying, a sales manager of real estate, is mean and indifferent, still remains single. She has never expected something like this would have happened to her. After her customers were gone, Jia found that she has left her personal phone at the model room. As she just stepped into the elevator, a horrid thundering comes, and the next thing she knew, she was waked from the dark, trapped among the destroyed elevator, and all she got was a cracked work phone, a lighter and a handbag. Jia managed to recover the phone and called for help, while the signal was fitful, and she cannot even remember her bes-tie or relative's number. The destroyed elevator fell again, iron stabbed into her thigh and caused badly bleeding. Jia kept trying on dialing, without the expectation to find a hidden conspiracy, as well as a bloody monster lurked deep in the dark.