身着一身白西装的戴夫（艾迪·墨菲 Eddie Murphy 饰）看起来是个彬彬有礼的中年人，虽然身处现代纽约的他总显得和这个年代、这个大都市格格不入，但谁能想到，这个看起来非常真实的“人”其实是一架人形飞船，身体里住着许多四分之一英寸高的外星小人，他们来到地球，想寻求解救自己星球的方法，不料却先在让飞船适应地球生活上经受了极大的考验，惹了一堆麻烦之后，谁想到飞船竟然自主爱上了一个美丽的地球女人吉娜（伊丽莎白·班克斯 Elizabeth Banks 饰），外星小人们偏轨的航线越来越难调正……A spaceship shaped like a human lands face first on Liberty Island. Its crew (of tiny, intelligent, and unemotional beings) is looking for an orb sent from its planet to extract the oceans' salt, which will ruin Earth. The orb is in the possession of Josh, the fifth-grade son of a single mom whose car strikes the ambulatory alien spaceship and cripples its power supply. The crew has 48 hours to recover the orb, throw it in the Atlantic, and leave Earth. Over the course of two days, the ship's crew experiences chaos and emotion in New York. Do Earth's giants - Josh and his mom - have anything to teach these brainy aliens? Meanwhile, mutiny is afoot and the cops are closing in.