High school twins Nick and Nora are hired by businessman Julius Wheeler to look after guests at his remote vacation home, deep in the Canadian wilderness. When the boat they're travelling on nearly sinks, Nick and Nora are stranded at the luxury cabin with eight unhappy, squabbling adults. Then, after stumbling across a massive meteorite hidden in the forest, members of the group begin to change and disappear. Instead of adventure and summer earnings, Nick and Nora must survive for the next seven days. As the dangers increase, the twins realise the terrible truth – a malevolent alien presence is taking control of the guests' minds and bodies. The remaining uninfected guests must quickly learn to set aside their differences and fight the deadly threat. Can reluctant leader Nick and resourceful Nora stay free of the invader? And can they figure out a way to destroy it before it's too late?