Three years after the green bomb wiped out humans in New York, rats Phil and Mike traverse the city following a wild, drunken night, searching for a missing car and encountering multiple species and terrors along the way.
Wallet, a diminutive, but fiercely heroic bird who leaves home after tragedy strikes, makes his way to Pigeon Heights. There, he becomes the right-hand man to recently crowned Pigeon King Phil, and is tasked with saving the day when terrorists take over a bar mitzvah.
In the new classist society that's been established among the equine community, a rich horse's daughter finds herself in a love triangle with a suitor approved by her father and a carriage horse from the wrong side of the tracks.
After a freak accident brings an assorted pile of random objects to life, the sentient items experience all of life's ups and downs on the path towards self-realization - and the meaning behind it all.
The "grabbags" - members of an inter-species group shunned by the rest of animal society - find themselves at the dawn of a new age when they are given the ability to communicate with one another, but ferret leader Yumi struggles to keep them all together. Meanwhile, geckos Phil and Mike plot to reclaim the above ground.
Estranged rat friends Phil and Mike are forced back together after a strange request sends them to the Democratic People's Republic of Kitty City, a feline section of town cut off from the outside world.