对于小狗麦克斯（帕顿·奥斯瓦尔特 Patton Oswalt 配音）来说，现世的生活幸福而美好。女主人凯蒂（艾丽·坎伯尔 Ellie Kemper 配音）的小宝宝降临人间，虽然让麦克斯感到些许的失落和威胁，但他很快找到自己的位置。他尽心尽力保护小主人，避免他受到一丁点外界伤害，为此疲于奔命而不自知。当随着主人一家去乡下度假时，新结识的动物朋友们使麦克斯绷紧的神经慢慢放松下来。 　　另一方面，兔子小白（凯文·哈特 Kevin Hart 配音）神经报表，经常被超级英雄的幻想附体。偶然间他发现马戏团中收到虐待的动物们，于是决心拯救他们于水火之中……Max faces some major changes after his owner Katie gets married and now has a child. On a family trip to the countryside, Max meets a farm dog named Rooster, and both attempt to overcome his fears. Meanwhile, Gidget tries to rescue Max's favorite toy from a cat-packed apartment, and Snowball sets on a mission to free a white tiger named Hu from a circus.