A group of aliens has come to Earth to learn about its population, customs, etc. To avoid detection, they have taken on human form which gives them human emotions, physical needs etc. WITHOUT the understanding of what they mean or the inhibitions normally present in humans. Their leader takes the position of a college professor, their military expert as his sister, their intelligence expert, supposedly oldest of group takes form of his teenage son. The uninhibited reactions turn everyday events into unusual situations.鲁韦道：“我掩护你们找机会逃命吧，我们的枪对它们根本没用，逃出去找到人类大部队，最好是有进化者保护你们，不然还是难逃丧尸的猎杀。”