The Avengers gather to celebrate their latest victory, but their celebration is quickly interrupted by the mysterious disappearance of Black Widow’s father, Red Guardian. As the Avengers investigate, they discover that Red Guardian isn’t the only one missing when they meet a dangerous new foe quite unlike anything they’ve ever encountered before.

居住在洛杉矶的除虫专家亚历克斯·马迪斯（格雷戈·格伦伯格 Greg Grunberg 饰）在一次工作中被褐皮蜘蛛咬伤，他到医院就诊，结果殓房一名医护人员被某具尸体里爬出的巨型蜘蛛攻击，留下难以置信的可怕伤口，正为医药费发愁的亚历克斯自告奋勇前去解决。与此同时，美国军方一对人马全副武装来到医院，宣布对此实施封锁。原来那只神秘蜘蛛来自军方的实验室，而错误送到医院的尸体无疑成为所有灾难的开始。在此期间，那只可怕的恶魔悄无声息出现在医院各个角落，并展开血腥的屠杀。