海西市郊山上有一个秘密养蛇基地，老板为了追求蛇皮高产，肆意投喂高激素饲料，蛇群逐渐变异……一天，重要客户上门考察，凶残的群蛇逃出牢笼，开始疯狂攻击养蛇基地的人类。基地里的人招架不住蛇群的攻势全部惨死。然而蛇群却并没有满足，它们爬向了养蛇基地外不远处的一所模特空乘女子学校......学校正在进行“2021毕业典礼”的筹备，不知自己即将面临危险的学生们，还在进行学校的专业技能大赛。蛇群隐秘的涌入了学校的各个场所，宿舍、澡堂、走廊、模拟机舱……数名女生被群蛇咬伤，尖叫声惊动了整座宿舍楼，女生们纷纷四散而逃。保安刘超解救了被蛇群困住的空乘专业学生李梦娜，二人想通知全校师生紧急撤离却被校长拦下，校长并不相信真的有什么变异蛇群，执意继续筹备毕业典礼。这时众目睽睽之下，巨型黑蛇把校长一口吞噬。终于，人蛇生存大逃亡正式拉开序幕……
新加坡重案组警察李顺杰是一个兢兢业业的男人，他的家庭和美幸福，充满欢乐，母亲（郑佩佩 饰）、妻子小梅以及妹妹小琴都以他为荣。然而一起与黑帮有关的案件却将他带入万劫不复之中，阿顺和卧底接头被黑帮发觉，致使卧底当街被杀，自己和妻子也在家中惨遭毒手。警员遇害的新闻在社会上引起轩然大波，也给李太和小琴的心中留下难以愈合的伤痛。在阿顺夫妇去世的第七天，也就是传统的回魂夜。小琴突然失踪，而当初杀害阿顺的黑帮分子接连被杀。原来阿顺的魂魄附到小琴的身上，对狂暴妄佞的展开无情的报复。因果报应，丝毫不爽。肃杀之夜，注定是血雨腥风
January is forced to return home after six years traveling abroad. A near-fatal accident has left her temporarily wheelchair bound and depleted of her long-term memory. She is accompanied by her boyfriend 'Callum' whom she met whilst traveling. He was also the driver in the fateful accident. Not only has she forgotten her family, but her childhood as well and is surprised to discover that her home is a stately manor in the middle of the country-side. As January tries to settle in, she finds herself becoming even more estranged from her family, who just want their daughter back. The trouble is, she cannot remember who that daughter was, or why she ran away in the first place. Desperate to discover why she left all those years ago and with Callum's help, she sets out to find the truth. They soon discover the family are not as loving as they seem to be. Was there a dark reason why she left them in the first place?
