讲述了年轻警官麦迪的故事，她决心继承已故父亲的遗志。当当地人被僵尸袋鼠残忍撕成碎片时，她的勇气受到了考验。当不死野兽留下大屠杀的痕迹时，麦迪在她古怪的叔叔施密蒂和坚韧的阿姨唐娜的帮助下，必须展开一场高风险的战斗来拯救这座小镇。

这部电影以赫德曼的孩子们为中心，他们是最糟糕的。他们撒谎，他们偷窃，他们欺负……他们劫持了镇上的圣诞庆典。当吵闹的兄弟姐妹们强迫自己出演所有主角时，他们把选美比赛的导演格蕾丝（朱迪·格里尔饰）和她的其他家庭成员，包括丈夫鲍勃（福尔摩斯饰），都推到了墙上。但通过他们不合适的恶作剧，这些不太可能的信使可能会成为传达该镇对圣诞节真正意义的耸人听闻和感人的描绘的人。

The film centers on the Herdman kids, who are the absolute worst. They lie, they steal, they bully… and they’ve hijacked the town Christmas pageant. As the rowdy and raucous siblings force themselves into all of the lead roles, they drive the pageant’s director, Grace (Judy Greer), and other members of her family, including husband Bob (Holmes), up the wall. But through their misfit mischief, these unlikely messengers might turn out to be the ones to deliver the town’s sensational and moving portrayal of the true meaning of Christmas.