In the suburbs of an American town, the Templetons live a happy life.
The son Tim adores his parents because as the only child, he gets all the attention.
He has an impressive imagination and plays all kinds of games that put him in imaginary
worlds that his parents often join.
Sometimes the parents help him defeat the monsters, other times they play the monsters
themselves.
Tim has the ability to make games out of even his daily tasks, like taking a bath and riding
his bike.
He thinks his parents are extra great because their job is cool too, since they work at
Puppy Co.
Every night, the parents come to Tim’s bedroom to wish him good dreams with a song and perhaps
a snack, and Tim is convinced he doesn’t want to share this with anyone.
So when his parents ask if he wants a sibling, Tim says no.
Meanwhile in the baby factory, newborns are being made.
A machine checks they’re well and healthy and gives them cute clothes before being sent
to a family.
However some babies show to be smarter than the others, and the machine chooses those
to go to the factory management, dressing them in sharp suits and even giving them little
watches and suitcases.
Hundreds of babies are working on management and they keep control of everything baby-related.
Back to Tim, he wakes up ready for another adventure, but when he looks out the window
he sees a taxi arrive to drop a baby.
Not just any baby, but it’s a Boss Baby, dressed in a suit.
He can’t believe what he’s seeing, and when he runs downstairs, he discovers his
parents with Baby in their arms without finding anything weird with it.
They inform Tim that this is his new brother and immediately Baby starts crying, demanding
attention.
Soon the parents don’t have time for Tim anymore because the Boss Baby needs to be
taken care of all the time, even in the middle of the night.
He’s always wanting to play, eat, or needing a change of diapers, and he throws a really
loud tantrum whenever he doesn’t get what he wants.
Now when Tim tries to have adventures around the house, he finds every spot of the house
filled with baby things, and even pictures and bath time must be shared.
One night, Tim tries to point out to his parents that Baby is too weird and they can’t trust
him, and when the parents aren’t looking, he even ends up in a tug-of-war with his brother
over the table.
Unfortunately his parents don’t see anything wrong with the suit and ignore Tim’s frustration.
One evening while his parents are sleeping on the couch because they’re exhausted,
Tim hears the phone ring.
He picks it up only to discover the call is coming from somewhere else in the house, so
he goes upstairs.
While pretending he’s on a creepy mission, Tim follows the noise and is shocked to find
out his brother can talk, in fact he’s having a chat through a toy phone.
Tim freaks out and demands an explanation, but Baby refuses to give it, saying he’s
on a mission and Tim wouldn’t understand.
To keep Tim’s silence, Baby tries to pay him off, but Tim doesn’t want money and
threatens with telling his parents.
Baby isn’t worried though because he knows nobody will believe him.
Using a bead toy, Baby explains business can’t be shared and that Tim has to back away or
he’ll get fired.
Tim goes to bed wondering if someone can truly be fired from his own family.
The next morning, Tim uses his imagination to have a conversation with the figurine on
his alarm clock and comes to the conclusion he needs to gather evidence of Baby’s secret.
After gathering homemade equipment to pretend he’s a spy, Tim comes downstairs and finds
a bunch of monsters, who turn out to be a bunch of babies his parents have brought for
a playdate.
When the adults aren’t looking, the babies pretend to play but they’re actually holding
a meeting about the mysterious mission.
They know Tim is spying on them and trying to record their conversation, so they make
noise with their toys to cover up their discussion.
It turns out that the babies are worried that puppies are too popular nowadays and are going
to take the place of children in a family when affection should always be directed at
babies.
To make matters worse, Puppy Co is going to launch the ultimate puppy in Las Vegas soon,
so they need to stop it.
Regardless of the noise, Tim manages to come closer and record the whole thing.
While the babies are distracted pretending to be innocent for their parents, Tim tries
to sneak away, but as soon as the adults are gone the babies block his way.
Then Tim runs to the garden to try to give the tape to his parents, but all the babies
show up again, this time riding toy vehicles.
A fast chase starts around the garden as the babies try to steal the tape, but when the
parents check on them, they only see children playing together.
Tim runs through the garden in specific spots to get the different babies stuck on various
objects.
However Boss Baby is too fast with his little car and steals the tape.
Then Tim goes to his treehouse and gets his toy gun to start shooting, but the big baby
protects Boss Baby from the dummy darts.
this distraction is enough for Tim to run by and steal the tape before jumping on a
trampoline to return to his room, so the big baby tosses the Boss through the window.
While the adults discover the mess outside, Boss Baby chases after Tim, who sends him
into the street.
However Tim finds Baby again in a room and is devastated to watch him destroy his favorite
plushie.
Having had enough, Tim tries to throw Baby out of the window, but at that moment his
parents catch him red-handed.
Tim throws out his tape by mistake instead of the baby, and a passing car destroys it.
Tim tries to tell the adults the truth, but nobody believes him.
His parents are furious by Tim’s behavior and decide to ground him for three weeks.
Tim was never grounded before, so he feels like he’s in jail.
To make matters worse, he has to hear how his parents sing the special song to Baby
at night instead.
Some days later, Baby feels bad for Tim and comes to see him, offering his sympathies
in a very awkward way and with money.
He points out that if Tim had left him alone, nothing would’ve happened.
Tim still wants to know what really is going on, so Baby gives Tim a pacifier and when
they start using it, their minds are transported to the Baby Factory as if they were holograms.
Boss Baby tells Tim about smarter babies getting chosen for Management, who drink a special
milk that stops them from growing.
He wants a promotion so he can get a better desk and office for himself, and to achieve
that, he must stop humans from liking puppies more than babies.
Then Baby takes Tim through a gallery with all the Management bosses from the past who
also got promotions from their missions.
His idol is Big Fat Boss Baby, the youngest boss in the history of the company who retired
some years ago.
At that moment, they see the current Management Boss demanding updates on the mission, so
Baby quickly makes them return home.
He panics because he hasn’t made progress with the mission and he has two days left,
he also explains that if he fails they’ll transform him into a normal baby.
That means he’ll be Tim’s brother for real.
Wanting to stop that from happening, Tim accepts to help Baby with his mission.
Since their parents work for Puppy Co, they need to find a way to go with them to the
company on Take Your Kid To Work Day.
Tim reminds Baby that he’s grounded, so to convince their parents that he’s good
now, they’ll have to pretend to get along and love each other.
For the next two days, Tim takes extra good care of his brother by feeding him, dressing
him, posing for pictures together, and reading him stories; although Baby gives him a hard
time through it.
Even though they won’t admit it, they start getting along too and they even fall asleep
together.
Their parents are very proud to see them get along and they cancel the punishment, so the
whole family gets to go to Puppy Co together.
The brothers put on their best clothes and when the parents offer Tim to spend a special
“Tim day”, Tim is heartbroken to say no because he has to keep his promise.
He says he’ll spend the day with his brother, then they pretend they’ll check out the
puppies but actually they’re sneaking around to get information.
Baby ends up dressing as a dog to enter a secret room and when other dogs try to play
with him, Tim distracts them with a ball.
To get rid of the guard, Baby licks his face and finally crosses the door.
Tim joins him seconds later and together they look around until they find the secret file,
but when they try to exchange it for another one to avoid a trap, Baby accidentally drops
drool on it and the security system reacts anyway.
Baby checks the file and sees it says “gotcha!”
before a creepy guard dressed as a dog sends them to the office belonging to Francis, the
CEO who has hired his brother Eugene as the guard in costume.
Francis then reveals he has a Baby Corp pacifier because he’s actually Big Fat Boss Baby,
who never retired.
He actually lost milk privileges because he was lactose intolerant, and since he was growing
old, he was fired and sent to Earth to grow up normally.
Furious, Francis built this company and as revenge, he has designed the perfect and cutest
puppy that will never grow old in order to make the world like dogs more than babies.
During the launch in Las Vegas, a rocket will drop puppies all over the world and this will
be the end of Baby Corp.
Baby doesn’t think a forever puppy is possible, but Francis proves him wrong by revealing
Eugene stole Baby’s milk from his bag, which he can now use on the puppies.
Tim threatens with telling his parents, but Francis isn’t worried: he’s ordered the
parents to work on launch day, and Eugene will pretend to be a company-assigned babysitter
that will take care of the children.
The parents leave without suspecting anything, and Eugene immediately locks the brothers
in Baby’s room.
To make matters worse, the enemy has stolen all the special milk, and there are moments
when Baby becomes a normal infant that doesn’t understand what’s going on.
This gives Tim an idea: he uses various objects from around the house and paints Baby’s
face to make him look sick, then he shows Eugene while activating a vacuum that shoots
fake vomit at the old man.
Disgusted by this, Eugene goes to the bathroom to wash, and the kids lock him there before
escaping on Tim’s bicycle.
However Eugene manages to escape and begins chasing them, so Baby calls his friends for
backup.
The baby gang attacks Eugene with a variety of tricks and toys, including tickling, but
Eugene can easily survive it all.
Baby decides Tim will have to drop the training wheels if he wants to go faster, but Tim is
terrified because he’s never done it before.
Luckily Baby offers the perfect pep talk and Tim gains courage through his fantasies, allowing
him to dodge all the obstacles and leave Eugene behind before reaching the airport.
Unfortunately it’s too late and their parents are already gone on their plane.
The brothers start arguing over whose fault is this and Tim tells Baby he wishes he was
never born, which hurts Baby so badly that he goes away.
Tim stays crying in the airport for hours, but when night starts to fall, he receives
a call from his brother.
Baby explains he never had a family before and doesn’t know how to act around one,
but he does care deep inside.
The brothers reconcile and make a plan to go to Las Vegas too: they notice there’s
a plane transporting only Elvis impersonators, so they steal the clothes from one of them
and pretend to be another artist to be allowed in the plane.
Being small kids allows them to sneak into first class, which is empty because nobody
can afford it.
Tim is afraid of the takeoff, so Baby holds his hand like their parents used to do.
When the stewardess brings them food, Tim teaches Baby how to use his imagination and
make an adventure out of a simple thing like lunch.
When they finally make it to Las Vegas, the kids don’t notice that one of the Elvis
was Eugene in disguise.
They make adorable faces at a group of partying women and convince them to take them to the
convention center, where Baby begins to behave like a real infant again.
At that moment Eugene arrives to chase them, so Tim has to pick up his brother as he runs
into a crowd.
At the same time on the main stage, Francis and the parents reveal the cutest puppy in
the history of humanity.
The crowd comes forward for a better look and exposes the children, causing their parents
to worry.
Francis immediately locks the parents inside a box and takes it away to put inside the
rocket and kills them with the ignition.
Then Francis begins chasing the brothers again, so the brothers run into a giant hamster house
called the Habitrail.
The pipes are perfect for them to run through, but they’re too small for Eugene and he
gets stuck.
At the end of the pipes, Tim and Baby find the rocket and a huge tank of special milk,
which Francis replicated using Baby’s in order to make thousands of forever puppies
that are now being put inside the rocket.
At that moment, Eugene finally reaches them and breaks the pipe to make them fall, but
the brothers jump out of the way just in time and Eugene falls into a litter box where he’s
attacked by cats.
The brothers run to the rocket only to find the way blocked by Francis, who starts the
countdown and throws the key to the box away.
Tim and Baby tickle him to move him away, but Francias quickly retaliates and causes
them to fall, leaving them hanging on the edge of the platform.
Baby suddenly remembers the imaginative lessons Tim taught him and pretends they’re pirates,
inspiring the brother to team up and fight Francis until he falls inside the milk tank.
Afterward, the siblings reach the ground by jumping on the puppies with parachutes and
Baby pulls a lever to free all the puppies, who take the locked box away as they run.
Tim realizes Baby is stuck on the rocket because he’s behaving like an infant again and he
doesn’t understand any words.
Thankfully Tim thinks fast and begins singing the special song, gaining Baby’s trust for
him to jump into his arms.
The brothers move to the side right before the rocket launches completely empty.
Then Tim takes Baby to the tank so he can drink some milk and be himself again.
Francis comes out of the tank too and reveals he’s a baby again, but before he can start
a fight, Eugene picks him up and promises to raise him well.
Next, Baby picks the lock on the box and frees the parents, allowing the family to finally
reunite and go home.
Sometime later, Baby gets ready to leave.
He says goodbye to the other babies and even allows the big one to hug him.
Then he says goodbye to Tim while gifting him back his plushie, which he has fixed.
A taxi comes to pick Baby up, and the brothers look at each other one last time while feeling
sad for some reason.
Shortly afterward, a special division from Baby Corp shows up at the house to modify
all pictures, take away all of Baby’s things, and delete the parent’s memories, making
it seem as if Baby had never been there.
Tim tries to return to his normal life, but he realizes things aren’t the same without
his brother even though he has his parents’ attention now.
Meanwhile at the company, Baby is received as a hero with a huge celebration and he gets
the big office he wanted, but he feels lonely and craving affection.
A few days later, Tim remembers the beads lesson and writes a letter to Baby.
When Baby receives it, he’s shocked to read Tim is willing to share everything and finds
a box full of beads just for himself.
Excited, Baby decides to quit with a huge dramatic scene, then he takes the normal path
in the factory to become normal.
The next morning, Tim comes downstairs and is happy to see his brother is back to stay
for good, and the parents name him Theodore.
The family then lives happily ever after.
This whole story is being told by an older Tim to his little daughter, who is worried
about the fact he’s having a sister soon.
Old Theodore is also there for support, and when they look at the new baby together, the
daughter is shocked to see her new sister is also wearing a suit.