生物学博士赛斯和妻子宝莉驾车去郊外游玩，路上，他们遭遇了另一对夫妇。丹尼斯和蕾丝是一对亡命鸳鸯，他们希望偷渡墨西哥开始新的生活，但是汽车在路上抛锚。因此，丹尼斯劫持了赛斯夫妇的汽车，并将他们绑作人质。 驾驶汽车的宝莉无意中轧到一个奇怪生物，引起汽车爆胎。众人下车查看，赛斯惊奇地发现被压扁的动物竟仍有生命迹象。

A fourth season of 12 episodes has been confirmed and will premiere on June 23, 2014 on MTV. This will be the first season not to star Crystal Reed. New cast additions include Meagan Tandy as Braeden (who only appeared in 2 episodes of season 3), Dylan Sprayberry as Liam, Khylin Rambo as Mason “an out-and-proud athlete” and Mason Dye as his best friend Garrett. Dylan O'Brien confirmed in an interview that Malia Tate (Shelley Hennig) would be a regular next season and joins the pack.