Maggie wakes on her tenth birthday, thrilled that her family has promised to let her adopt a puppy.

Maggie finds a puppy she loves at the shelter but has a severe allergic reaction during the adoption paperwork.

Allergy tests at the Family Allergy Center confirm Maggie is severely allergic to animals with fur or feathers.

Dr. Idonjie tells Maggie's mom that Maggie cannot have any pets with fur or feathers, even hypoallergenic breeds.

Maggie tears pictures off her walls and knocks things off her shelves after learning she can never have a dog.

Maggie's eight attempts to find a suitable fur-free pet all fail, and she throws away her list in frustration.

Maggie's first day at a new school is derailed when she cannot stop sneezing around the class guinea pig.

Maggie meets new neighbor Claire, who invites her in for pizza and immediately talks about all the fun they can have.

Maggie saves up money and buys Claire a BFF heart necklace to celebrate their close friendship.

Maggie sees Claire holding a new puppy and rips off the friendship necklace, refusing to speak to Claire.

Maggie convinces her parents to install a door lock, then secretly sneaks a pet mouse named Pipsqueak into her room.

Maggie's brothers discover the secret mice and tell their grandmother; Maggie's dad takes all the mice to the pet store.

Maggie's mom goes into labor; Maggie runs back to remind her to breathe deeply before the car drives away.

Maggie holds crying baby June for the first time at the hospital, soothes her, and suggests the name June.

At the aquarium with her mom and June, Maggie decides she wants to become a marine biologist.

Maggie Wilson's story begins on her tenth birthday, when she expects to finally adopt a puppy — only to discover she has a severe allergy to all animals with fur or feathers. Devastated, she cycles through every pet option she can think of, but nothing fills the void left by the dog she can never have. Starting over at a new school without her friends makes things worse, but a neighbor named Claire becomes her first real companion. Their friendship is tested when Claire adopts a puppy, and the secret pet mouse Maggie smuggles home only leads to more heartbreak when her parents make her return it. Everything shifts when her new baby sister is born: Maggie names her June, learns to care for her, and slowly realizes that the companion she was searching for has been growing right in her own home all along.

The headline events of Maggie's journey from wanting a puppy to finding her place in the family.

Maggie's family drives to the shelter with her parents in front discussing baby names while Maggie sits alone in the middle row.

The family leaves the shelter planning to return for the puppy once Maggie is better, but Maggie narrates that they never do.

Maggie spends her birthday night lying on the couch with bandages and an ice pack, feeling completely miserable.

Maggie tries to use willpower to prevent a reaction during allergy testing, but her arms swell and itch intensely.

The doctor mentions allergy shots, which panics Maggie; her mother tries to comfort her on the drive home.

Maggie makes a list of possible pets without fur or feathers after finding a book about turtles in her bedroom.

Maggie's twin brothers blame her for the family not being able to adopt a dog because of her allergies.

Claire and Maggie bake cupcakes together; Maggie mentions that she used to want to become a veterinarian.

Maggie tells her parents her grand plans to redesign the whole house; her mom suggests she start with her own room instead.

Sixth-grade friends are surprised Claire befriended a fifth grader, but Claire tells them Maggie is awesome.

Claire and Maggie have a water balloon fight with Maggie's brothers and build a fort; Claire reveals her parents are divorced.

Maggie receives her first allergy shots and notices the baby car seat already installed in the family car.

Sebastian describes his egg allergy and tells Maggie about the anaphylactic reaction that once sent him to the hospital.

Maggie marks on her calendar the date when she can finally touch the newborn baby mice and diligently cares for them in secret.

The morning after the new baby is born, the children make birthday pancakes together just as their father always does on birthdays.

While the main plot tracks Maggie's allergy diagnosis and her search for a pet, a rich layer of secondary events shapes who she becomes. The birthday trip to the shelter reveals the family dynamics that drive Maggie's loneliness, and the string of failed pet quests shows just how determined she is to find a companion. New friendships with Claire and Sebastian grow through small shared moments — baking cupcakes, building forts, and swapping facts about allergies — that matter as much as any dramatic turning point. Meanwhile, tension builds at home as the baby's arrival looms and Maggie struggles to accept the changes coming her way. By the time the children gather to make birthday pancakes the morning June is born, it becomes clear that the family bonds Maggie underestimated have been quietly strengthening all along.

The quieter but meaningful moments that show how Maggie's world changes around her.

Maggie reaches for her mother's hand at the allergy clinic, but her mother unknowingly pulls it away to touch her pregnant belly.

Maggie starts to cry when the nurse tells her the allergy test confirms she is allergic to dogs.

Dr. Idonjie gives Maggie a comic book explaining how an overprotective immune system causes allergic reactions.

Maggie's whole family breaks into roughhousing and laughter together on the floor, showing a warmth Maggie often overlooks.

Maggie arrives at her new school feeling tiny and lost; one illustration depicts her reaching only to other students' ankles.

The class guinea pig is moved to another classroom after Maggie's mom calls the school, and Maggie feels it is entirely her fault.

After reconciling with Claire, Maggie accepts Claire's suggestion that a small mouse might not trigger her allergies.

Maggie wakes abruptly one morning and discovers Pipsqueak surrounded by a circle of many tiny newborn baby mice.

Maggie's mom uses her nickname 'sweetie' for the unborn baby; Maggie storms off and accidentally drops her room keys.

While doing homework outside, Maggie spots Claire crying through a hole in the fence and realizes she never considered Claire's feelings.

Maggie goes to Claire's house to apologize; Claire explains she got the dog believing allergy shots would let Maggie be around dogs.

After losing the mice, Maggie furiously blames Claire for originally suggesting the mouse; Claire walks away angry.

Maggie's dad sits with her on the bedroom floor, validates her feelings of loneliness, then explains why the mice must go.

Maggie sleeps on the floor of her brothers' room to comfort Liam, who asks why she never seems to like him and Noah.

Maggie's dad insists she gets to hold baby June first; her mother calls Maggie 'sweetie,' and Maggie smiles before going to wash her hands.

Maggie's growth happens not in grand gestures but in sharp, pivotal moments where her perspective shifts. From the small sting of reaching for her mother's hand and being left unnoticed, to the shock of watching her allergy test results bloom on her skin, each early revelation deepens her sense of being alone in a crowded family. Her friendship with Claire produces its own turning points — a broken necklace, a tearful face glimpsed through a fence, and a difficult apology that begins to teach Maggie what empathy actually feels like. A midnight conversation on a bedroom floor with her brother Liam cracks open the assumption that no one in her family truly needs her. By the time she stands in the aquarium watching her baby sister point at a shark, every one of these small moments has added up to a Maggie who finally understands her own luck.

The key discoveries, emotional breakthroughs, and decisions that mark Maggie's growth.