Upon their graduation, Xiao Long, Le Le and Mei Mei made a promise to get into the key middle school of the city together. Le Le did it with his performance, and Mei Mei was admitted because her father pulled strings. However, Xiao Long’s father asked Xiao Long to come back to Shanghai to study. Xiao Long didn’t want to leave, and he also felt betrayed by Le Le and Mei Mei. He ran away from home with his cat, lived on an abandoned rooftop and supported himself by selling cables. Finally, Mei Mei and Le Le found him, and they promised to go to Shanghai together in the future.
原始人咕嚕一家口在老爸Grug（尼古拉斯·凱 Nicolas Cage 配音）的庇護(hù)下生活每天搶奪鴕鳥蛋食，躲避野獸的擊，每晚聽老爸述同一個故事，山洞里過著一成變的生活。大女Eep（艾瑪·斯通 Emma Stone 配音）是一個和老爸性截然相反的充滿奇心的女孩，她滿足一輩子留在個小山洞里，一想要追逐山洞外的新奇世界?
