In the labs of ExoFarm, a mysterious scientist is conducting some experiments using ants when
suddenly, his arthritis hits him in the leg with excruciating pain. The scientist flails
and falls back, accidentally hitting the tools on his desk, making them fall. This allows the
ant he had been experimenting on to escape. Months later, twelve-year-old Pelle is trying to survive
middle school. He's tired of everyone ignoring him because he's extremely bland and boring, people
don't even get his name right. He wishes for any kind of attention, even if that meant being the
nerd everyone teases. Not having friends or any kind of social interaction makes him feel tiny and
insignificant. The attention he wants the most is his crush Amanda's, but she doesn't know he even
exists. When it's time to take the class pictures, even the photographer barely notices Pelle and
gets his name wrong. In the final group picture, only the top of Pelle's head can be seen, further
proving how little they care about him. Later during class, the teacher gives the students a new
assignment: they need to make a presentation on an interesting person in town, making a poster with
pictures and facts about them. Amanda's sister Ida points out there aren't interesting people
in their little town, and the teacher reminds her that the sisters' dad Mr. Sommersted is the
CEO of Exofarm, so that should be a good place to start. This assignment has to be done in pairs,
and for a moment Pelle thinks Amanda is asking him to be her partner, but she's actually talking
to the girl behind him and he's going unnoticed again. After school, Pelle is spending time by
himself on the roof when he sees two older kids making fun of Wilhelm for being a nerd and liking
comic books. Pelle decides to help by throwing his apple at the boys, getting them to back away,
then he tries to hide behind the roof. He would've gotten away with it if wasn't for a teacher that
sees him from through the window and calls him out for being on the roof, now the boys can see
him as well and begin chasing him through town. Pelle is faster than them but he doesn't know how
much energy he has to keep going, so he decides to hide in the garden of a very spooky house, where
an ant begins crawling up his leg. The boys hear some noises and guess Pelle is in that garden,
but they don't dare to enter because this house belonged to Mrs. Gamelkra, who died in mysterious
circumstances and now there are stories going around about the house possibly being haunted.
After the boys leave, Pelle decides to check out the house when suddenly, the ant crawls up his
body and bites his neck. Pelle begins feeling dizzy and falls to the ground, where his blurry
vision lets him see a human shape approach him. Before he can ask what's going on, Pelle passes
out. By the time he wakes up, night has fallen. Pelle returns home, where he's scolded by his
mother for coming back so late, so Pelle makes up some lie about losing track of time while playing
with a schoolmate. Then he goes to bed without having dinner because he's tired yet not hungry.
Once he falls asleep, Pelle can't stop having dreams about ants, and he ends up waking in the
middle of the night to sleepwalk to the kitchen in order to have a feast. The next morning, Pelle
doesn't remember anything and is shocked to see his bedroom full of food packages and leftovers,
not to mention the stains on his lips and cheek. Afterward he has breakfast with his parents,
who are watching an interview with Mr. Sommersted about a flea epidemic in town. While his mother
realizes somehow they're out of sugar, Pelle tries to add milk to his cereal, only to get
the carton stuck in his hands. It isn't until his father takes it away that he can let go of it.
Then Pelle tries to drink some juice, but by just picking up the glass, he breaks it. Moments later,
Pelle is running late and when he rushes into the school, he bumps into Wilhelm. He helps him
pick up his comic book before approaching the classroom, only to accidentally break the door
right in front of Wilhelm's eyes. Later during gym class, Wilhelm can't stop staring at Pelle,
especially when the teacher asks for a volunteer to demonstrate the next exercise and picks Pelle
for being the only one not to raise a hand. This exercise consists of fighting with pugil sticks,
and the teacher takes advantage of his bigger size to beat Pelle to the ground twice in a
row. Pelle feels humiliated, but when he notices Amanda watching him, he puts himself together and
tries again with more determination. This time, Pelle easily dodges and blocks the teacher's
moves before hitting him back, causing him to fly across the room. Scared of his own body,
Pelle runs away, leaving Wilhelm in shock. After school is over, Wilhelm follows Pelle to try to
get him to confess what's going on because he's sure Pelle is some kind of superhero. While
Wilhelm keeps babbling about possible powers, Pelle stares at a mysterious man parking in
front of Mrs. Gamelkra's house, thinking he looks familiar but not recognizing him as the shape he
saw when the ant bit him. Wilhelm keeps babbling, so Pelle accepts to borrow the comic book he keeps
offering just to get him to shut up. While Pelle leaves Wilhelm behind, the man enters the house
and looks at an article about Mr. Sommersted in the newspaper, promising revenge. Later at home,
Pelle stares at a picture of Amanda, thinking how he acted rather impressively in front of her
today, and decides to give Wilhelm's comic book a try. Once he's learned more about superheroes,
he begins playing with some toys pretending he's a hero and saving Amanda from the bad guys. He
gets so into it that when he throws a punch, he accidentally destroys his teddy bear and his
bedroom door. The next day, Pelle gives Wilhelm the comic book back and finally admits he's been
bitten by an ant. Wilhelm is super excited to hear this and accepts to help Pelle with his superhero
journey, taking him to his house where he keeps all kinds of hero merchandise. First they need
to know what kind of powers Pelle has, so they watch a documentary about ants to learn more
about them. Pelle has super strength because ants can lift several times their own weight,
he also has an ant's sharp mandibles that allow him to bite through anything. Ants have a great
sense of smell too, and by blindfolding Pelle, Wilhelm confirms he has it too by making him test
his nose on various meals. There are certain rare antes that can fly, but when Pelle tries, he just
falls on the ground. Ants can defend themselves with their formic acid, and Pelle discovers his
own pee can now destroy objects. Lastly, the most important thing in a male ant's life is the queen,
explaining Pelle's obsession with Amanda. If Pelle is going to be a superhero, he's going to need a
costume. They try to put something together with the things they find around the house
but they look ugly as heck, so Wilhelm orders some costumes online and combines them into an
actually cool-looking suit. Then the boys go to spend some time at the supermarket's parking lot,
looking for some crime. There's an argument about what Pelle's superhero name will be,
and after lots of bad ideas, they decide "Antboy" will do for now. With all the waiting, Pelle is
starting to feel hungry and Wilhelm accepts to go buy something for him. As soon as he's gone,
Pelle notices a thief stealing the wallet from a lady, and after changing into his costume,
he goes after him. The thief laughs when he sees Pelle's costume, causing the poor boy to get
intimidated and babble about stealing being wrong and how the thief should get an education. As the
thief starts coming closer, Pelle backs away in fear and ends up hitting a wall, but this doesn't
stop him and he just begins to unconsciously crawl on it. Now it's the thief's turn to feel scared,
and Pelle sees this opportunity to strike, jumping on the thief before he can run away. Moments
later, Wilhelm returns to the parking lot to see the police arresting the thief while he whines
about a scary little kid. Pelle calls Wilhelm from his hiding spot to tell him about what happened,
but when he tries to show how he can climb walls, it doesn't work. Pelle also feels incredibly
hungry again, and Wilhelm realizes that like ants, Pelle needs sugar to get energy, so his powers
stop working if he doesn't recharge. To complete the Antboy costume, Wilhelm gives Pelle a belt
with candy to recharge any time, a new cover for his phone, and an earpiece he calls the AntCom
which can be connected to Pelle's phone, that way they can always stay in touch while they go on
adventures. From then on, Pelle begins working as a superhero in his free time with Wilhelm's help,
saving people from all kinds of dangers like car crashes and fires, but also stopping the bad guys
that bother the innocent at school. Antboy soon appears all over the news and people love him,
giving Pelle the attention he's always wanted. There's merchandising like shirts and dolls,
the school play will be about him, and even Amanda starts getting a crush on Antboy to
the point she uses him as the subject of her presentation. Pelle loves to sign autographs
and appear in interviews as Antboy, which prompts Wilhelm to talk to him in private one afternoon,
explaining that heroes should be out helping people, not using their power to get fans. Wilhelm
believes Pelle just wants to be popular and points out girls will never care about the real them,
just about the superhero, but Pelle doesn't care because the attention Antboy gets is enough. One
evening, Amanda is busy working on her project when she suddenly hears a noise on the balcony.
It turns out a supervillain known as The Flea has come to kidnap her, and when Ida comes over after
hearing her sister screaming, it's too late: The Flea is leaving with Amanda over his shoulders,
only leaving the girl's necklace behind. The next day at school, Pelle is disappointed to hear the
sisters didn't come because Amanda is sick. Suddenly the class is interrupted by cries of
help from a student that is about to fall from the roof, so Pelle changes into his Antboy costume and
climbs the wall to save him after ignoring an incoming call from his mother into the AntCom.
Pelle pushes the boy inside the building only to discover it's a doll with a recorder, all this
has been set up by Ida to make the famous Antboy show up in front of her. She explains her sister
has been kidnapped and the Flea sent a video with a threat saying he'll kill Amanda in forty-eight
hours if Mr. Sommersted doesn't pay twenty million dollars and quits his CEO position at ExoFarm;
he'll also hurt Amanda if they call the police. Pelle wonders why Mr. Sommersted won't pay and
Ida points out that her family isn't that rich, thus Pelle accepts to rescue Amanda with the
help of Wilhelm. Saying that name aloud is an accident, and now Ida wants to go with them and
help as well. Pelle has no choice but to bring Ida with him to Wilhelm's place, which Wilhelm hates
because he thinks girls always ruin everything and can't keep a secret. Ida interrupts his rant
to ask to be taken seriously, and after playing the video again, Wilhelm is even angrier. He
thinks Mr. Sommersted like all CEOs is an evil businessman that only pretends to care about
the little person and he could totally pay that money, especially when Ida explains lots of people
dislike her dad and that he says it's lonely being at the top. The trio starts thinking about who
could possibly hate Sommersted this much and Pelle notices that Ida is carrying Amanda's necklace,
which still has her scent. Pelle uses his nose to track Amanda down through town and after wandering
around in their bikes, the trio makes it to Mrs. Gamelkra's house, the same place where Pelle got
his powers. Ida and Wilhelm are worried because Mrs. Gamelkra was found dead last summer after her
body rotted on the floor for two months so there are a lot of creepy stories going around, but
Pelle can't allow Antboy to get scared and enters the house anyway. He finds a door at the back that
is locked, so Pelle gets it open by peeing on it with his acidic urine. Once inside, he discovers
he's in some kind of basement laboratory filled with plants and creepy crawlies. At the very back,
Pelle finds Amanda locked inside an unbreakable glass cage, and while he's trying to find a
way to free her, the Flea appears behind him and pushes him into the cage as well. When Pelle asks,
The Flea is glad to share his backstory. He used to be a chemist at ExoFarm conducting research
with a very rare species of ant that has unique antibodies capable of killing life-threatening
illnesses. He developed a serum with the ant's healing powers and tested it on his own mother
Mrs. Gamelkra, confirming The Flea is the guy Pelle saw in the house when he was bitten. The
serum made Mrs. Gamelkra's tumors smaller, but then Sommersted implemented his cutbacks, The
Flea's research was terminated, and Mrs. Gamelkra was left to die. Afterward, The Flea began working
on his revenge, and his experiments change from ants to the flea of blood. When he consumed the
new serum, the flea's properties removed the arthritis in his legs and made them 100 times
stronger, but the transformation also made him crave blood, so his suit has two tanks full of
it in order to recharge. Then The Flea begins attacking Pelle with psychological low blows,
revealing he knows his secret identity and that the ant that bit him was the last of its kind,
so Pelle should be thankful to a villain for his powers. Amanda loves Antboy, not Pelle,
and Wilhelm is only interested in him for his powers, not because he wants his friendship.
Underneath the costume, Pelle was still an insignificant loser. The conversation's suddenly
interrupted by the police sirens, having been called by Wilhelm and Ida after they lost contact
with Pelle. The Flea escapes using his flying powers and the cops rescue Amanda and Pelle, who
finds himself with his spirit broken. He thinks The Flea was right, nobody really loves Pelle, and
he shouldn't be risking his life for people that don't care about him. When Wilhelm points out they
should go after The Flea, Pelle refuses and gives the helmet to him, telling him he can be Antboy
from now on because he quits. Wilhelm stares at the helmet, actually considering the idea. The
next day at school, Pelle and Wilhelm ignore each other. The classes are suddenly interrupted by an
attack from The Flea, so everybody starts running outside. Wilhelm asks Pelle for Antboy, but Pelle
says this isn't his problem and he'll let the cops handle it. After Pelle joins the others outside,
Wilhelm puts on the Antboy helmet and grabs two cans of insecticide to go after The Flea. As he
walks down the corridor, he finds a girl hiding inside some furniture and makes her go away, but
when The Flea finally finds him after destroying many walls, Wilhelm isn't quick enough to avoid
getting captured. Outside, the little girl tells everyone that Antboy saved her, and Pelle realizes
it must be Wilhelm. Worried about his friend, Pelle rushes inside to look for him and finds
the costume the school made for the Antboy play, so he puts it on before going after the Flea. When
the villain sees him, he removes the helmet from Wilhelm and realizes he's been tricked,
thus he takes the boy hostage instead. Pelle wants to help but he's starting to get hungry,
and since this isn't his real suit, it doesn't have the sugar refills. The Flea immediately
notices this advantage and begins breaking walls again, this time also throwing Pelle out of the
room. This puts him close to a vending machine, and Pelle manages to put his hands on some soda
that he drinks to recharge his powers. Noticing this, The Flea decides to fly away with Wilhelm
to hide in the woods. Pelle runs outside and Ida tries to offer her help, but Pelle promises he's
got this. After using his super teeth to destroy a lock, Pelle steals a bicycle and makes his way to
the forest as well. When he arrives at the forest, Pelle finds Wilhelm's glasses on the ground and
uses the smell to find him tied to a tree. After freeing him, he begins hearing The Flea's voice
telling him his real weakness isn't the lack of sugar, but his loved ones. Then The Flea jumps
from a tree and appears between the boys, kicking Pelle away and scaring Wilhelm to run in the
opposite direction. Once he's far enough, Wilhelm calls Pelle to confirm he's ok, and Pelle tells
him he has a plan. When The Flea goes after him, he finds the helmet and the cap on the ground,
and Pelle shows up at a safe distance. Pelle keeps him distracted by insulting him and daring him to
recharge so they can fight one-on-one in a duel, The Flea takes the bait and opens his tanks to
drink some blood. Since Pelle is keeping him distracted, Wilhelm approaches The Flea from
behind and messes with the tanks to make them lose blood. After Pelle recharges as well, hero
and villain run towards each other to end it all with one punch, and Pelle easily lands his first,
sending The Flea Flying against a tree. Because his tanks are empty, The Flea's weak and his
arthritis is affecting him again. Pelle points out he lost because he doesn't have friends to help
him during the hard times, but The Flea refuses to give up and tries again, only to be thrown away by
Pelle's super strength. After The Flea passes out, Pelle gives Wilhelm his glass back and
they reconcile. Later in the evening, The Flea is arrested by the police, and Sommersted appears on
tv denying any responsibility. Amanda is putting some lipstick on, expecting a visit from Antboy,
but when he finally shows up and she tries to thank him with a kiss, Pelle turns her
down and asks for Ida so he can return the necklace. Hurt, Amanda runs out of the room,
and Ida comes in, confessing she knows Antboy's real identity but also promising she won't tell.
Ida and Pelle thank each other for their help and accept to become friends. Sometime later,
Wilhelm approaches Pelle with the idea of making a costume for himself to be a proper sidekick,
and Pelle loves it. Together with Wilhelm and Ida, he knows he'll be invincible.