Taking place in a Manhattan apartment building, Max’s life as a favorite pet is turned upside down, when his owner brings home a sloppy mongrel named Duke. They have to put their quarrels behind when they find out that an adorable white bunny named Snowball is building an army of lost pets determined to take revenge

A dog named Max’s peaceful life is interrupted when his owner brings in Duke, a large dog Max highly dislikes. They quickly get into trouble and are sent to the pound. Max’s best friend Gidgent and a diverse group of pets journey to find them.