位于纽约的一栋红色公寓中，狗狗麦克（路易·C·K Louis C.K. 配音）陪同它的主人凯蒂（艾丽·坎伯尔 Ellie Kemper 配音）过着通俗而侥幸的生存。它不大白主待遇何天天早出晚回，总停整理凯蒂能不时刻刻陪同着它。此日傍晚，主人带回了一条体态重大的狗狗杜垂老（艾瑞克·斯通斯崔特 Eric Stonestreet 配音），整理时让麦克感觉如天塌了一般…

A young newlywed couple find themselves trapped in a network of underground caves. With her husband injured, the new bride is forced to find her way back to the surface in order to save his life. In the process, they discover a terrifying truth about the "underneath", they are not alone. Something evil is hun…