地球毀滅的一千年後，人類被迫離開地球遷往諾瓦星球（Nova Prime）定居。傳奇艦長西佛雷吉(威爾史密斯飾)剛從銀河系完成任務，準備返家照顧久未謀面的13歲兒子奇泰雷吉(杰登史密斯飾)。

一場行星風暴卻摧毀了他們的太空船，雷吉父子被迫緊急降落面目全非而充滿危險的地球。奇泰因父親西佛重傷臥倒於座艙奄奄一息，必須盡快修復飛船與勇敢跨越未知領域發出求救訊號，同時，他也必須面對已在地球上進化的各種可怕生物以及兇猛的外星怪獸......從小即渴求與父親一樣勇敢的奇泰，如何衝破父子間的隔閡化解致命困境，找到回家的路？

戲裡戲外皆為父子檔的威爾史密斯與杰登史密斯，在片中為求生存，有不少的驚險動作場面與精采的內心戲，對於未成年的傑登史密斯而言，不論是在演技或體能方面都是相當大的考驗。

One thousand years after cataclysmic events forced humanity’s escape from Earth, Nova Prime has become mankind’s new home. Legendary General Cypher Raige (Will Smith) returns from an extended tour of duty to his estranged family, ready to be a father to his 13-year-old son, Kitai (Jaden Smith). When an asteroid storm damages Cypher and Kitai’s craft, they crash-land on a now unfamiliar and dangerous Earth. As his father lies dying in the cockpit, Kitai must trek across the hostile terrain to recover their rescue beacon. His whole life, Kitai has wanted nothing more than to be a soldier like his father. Today, he gets his chance.