山姆(凯文·克莱恩 Kevin Kline 饰)和妻子结婚多年,两人感情十分要好,然而,腿脚的不便削减了山姆本该享受的快乐,再加上一个负能量爆棚的邻居,山姆觉得人生似乎失去了乐趣。阿尔奇(摩根·弗里曼 Morgan Freeman 饰)和儿子相依为命,可是,性格过于严厉的儿子令阿尔奇感到透不过气。派迪(罗伯特·德尼罗 Robert De Niro 饰)刚刚失去了挚爱的妻子,这让他的生活瞬间陷入了一片空洞和苍白之中。比利(迈克尔·道格拉斯 Michael Douglas 饰)正在着手准备他和年轻妻子的婚礼,这几乎成为了他生活的全部。 四个人至暮年的老人,四位患难与共的好友,当他们重新聚集到一起,决定最后疯狂一把去拉斯维加斯参加单身派对之时,会有怎样有趣的故事发生呢?Billy (Michael Douglas), Paddy (Robert De Niro), Archie (Morgan Freeman) and Sam (Kevin Kline) have been best friends since childhood. So when Billy, the group's sworn bachelor, finally proposes to his thirty-something (of course) girlfriend, the four head to Las Vegas with a plan to stop acting their age and relive their glory days. However, upon arriving, the four quickly realize that the decades have transformed Sin City and tested their friendship in ways they never imagined. The Rat Pack may have once played the Sands and Cirque du Soleil may now rule the Strip, but it's these four who are taking over Vegas.