Phil Jr. and Mike find themselves losing their minds, as they begin to believe that they are in a love triangle with an imaginary friend, after being abducted as lab rats. After being stuck on a monkey's back, two fleas contemplate life, while an algae wonders about its purpose in life.
Pigeon Mike's son Jacob embarks on a self-discovery journey after feeling jealous over his little brother. Two foxes express the struggle they go through in the city streets through rapping.
A group of roaches attempt to break free of their wall and head to the outside world, after an exterminator jeopardizes their existence. After getting stuck by a piece of litter, a group of seagulls fight to survive.
As New York is in crisis after being quarantined, squirrels Mike and Phil are getting ready for their mother's remarriage. In an attempt to sabotage the wedding, Phil challenges his soon-to-be little step-brother, the hog Mason.
The mad scientist Dr. Labcoat is getting ready to release a mysterious cure for the virus that would turn those who take it into his slaves.
As rats Mike and Phil Jr. plot to take advantage of a human baby, things start to get out of control. Meanwhile, two bees discover the secret of pollination.
On the streets of Little Italy, alley cats fight for domination while a young feline shows its skills. Three owls get together to celebrate Christmas.
New York's alley cats are getting ready to settle their power struggle once and for all. Elsewhere, Phil is taking charge while Mike is looking for a way to escape.
The food chain is examined through three stories: the journey of two ends of a worm to find love, a pair of newly-hatched bluebirds struggle to survive and a clash between an opossum father and son over the fact that they are predators.
As the old dog Dorothy looks back at her life, Dr. Labcoat makes a fateful action that will affect the whole city of New York. As their high school graduation gets closer, Mike and Phil Jr. might head in different directions.