格雷姆(西蒙·佩吉 Simon Pegg 饰)与克莱夫(尼克·弗罗斯特 Nick Frost 饰)是一对来自英国的极客好友,每天生活中充斥着外星人事件、漫画故事、科幻点子,今次又跑到美国来参加漫展,顺道探访外星人爱好者圣地:内华达州51区,没想到在路上偶遇一个真正的外星 人——60年前被困在地球,又被科研基地囚禁研究,而今终于逃出来的保罗(塞斯·罗根 Seth Rogen 配音)。不出所料的是,保罗长得一副ET样,超能力一流,而出乎他们意料的是,保罗是个满口美式俏皮话和脏话的“痞子”外星人,三个难兄难弟走上“帮保罗回家”的路途,后面紧追不舍的是国土安全局探员佐尔(杰森·贝特曼 Jason Bateman 饰)和他的笨搭档,一心想抓保罗回研究基地…… 本片是英国金牌喜剧搭档西蒙·佩吉和尼克·弗罗斯特继《僵尸肖恩》和《热血警探》之后再度爆笑合作。Two sci-fi geeks take a pilgrimage to America's UFO heartland. While there, they accidentally meet an alien who brings them on an insane road trip that alters their universe forever. For the past 60 years, an alien named Paul (voiced by Seth Rogen) has been hanging out at a top-secret military base. When he discovers he's been taken prisoner, the space-traveling smart ass decides to escape the compound and hop on the first vehicle out of town - a rented RV containing Earthlings Graeme Willy (Simon Pegg) and Clive Gollings (Nick Frost). Chased by federal agents and the fanatical father of a young woman that they accidentally kidnap, Graeme and Clive hatch a fumbling escape plan to return Paul to his mother ship. And as two nerds struggle to help, one little green man might just take his fellow outcasts from misfits to intergalactic heroes.