The story follows Sam Krupnik from birth through his early years, told from his perspective as he makes sense of family life, language, and the wider world.
Sam arrives as a newborn in a hospital, confused by bright lights and cold air. He cannot communicate; every attempt to speak comes out as "Waaaahhhh." Three faces lean over his bed: his mother, his bald, bearded father, and a girl wearing glasses who touches his hand. Sam grabs her finger, and she announces that she likes him. The girl, his older sister Anastasia, has chosen his name. The family greets him one by one: "Hi, Sam."
Three days later, the family takes Sam home. Anastasia holds him during the car ride and explains that his bedroom is a converted pantry with blue walls, a crib, and curtains decorated with unicorns. Sam, mishearing, thinks of it as a "pan tree." In the weeks that follow, his life revolves around sleeping, feeding, and being carried around the apartment. He loves the "blurble blurble" game his mother plays on his tummy during diaper changes and cries when his father and Anastasia skip it, until his mother teaches them the routine. At night, he practices talking secretly in his crib, whispering sounds to himself.
One day, left alone on a blanket on the living room floor, Sam discovers he can roll. He rolls across the room and hides under the green chair. Anastasia discovers the empty blanket and panics, convinced Sam has been kidnapped. She mistakes a grocery list for a ransom note. Sam laughs and rolls out, delighting the family.
On a Saturday morning, while his father reads the newspaper, his mother knits, and Anastasia secretly paints her father's big toenail red, Sam pulls himself upright using the coffee table, lets go, and walks across the room. He calls out: "SEE ME? I'M UP!" His mother spots the walking, Anastasia notices the talking, and his father bellows about his painted toenail. Sam falls but is thrilled by the possibilities walking opens up.
Now mobile, Sam becomes curious about how things work. His mother explains that water goes down the drain, through pipes to the ocean, then rises and rains back down. Sam investigates his father's tobacco pipes, expecting to find water inside, but finds none. He begins dropping objects into the toilet, planning to flush them so they will rain down. His mother catches him and explains that those things do not like being in water. Sam interprets the lesson literally: He needs something that does like water. He fetches Anastasia's goldfish, Frank, places Frank in the toilet, and flushes. Anastasia cries. That night, Sam watches the sky from his crib, hoping it will rain goldfish, but it never does.
Sam enters the phase his mother calls the "Terrible Twos," which puzzles him because he cannot find any Terrible Twos anywhere. He enjoys saying "no" to everything. When his mother urges him to be "trained," Sam, who loves
The Little Engine That Could, associates the word with trains and begins chugga-chugging down the hall. When she clarifies the concept of toilet training, he refuses emphatically and chugga-chugs away, singing "I thought I could."
When Anastasia announces the family is moving, Sam takes the word literally: He is sitting still and insists he is not moving. On moving day, Sam admires the tattooed movers so much he draws a tattoo on his own arm with a blue marker. The new house overwhelms him with its size. He gets lost and is frightened by his big empty bedroom, especially its closet. Anastasia eases his fear by setting up a cardboard-box garage in his room, and the whole family, along with the movers, gets on hands and knees to push Sam's trucks down the hall, making engine noises. After this communal play, Sam agrees to have his bed placed in the room, insisting it is a real bed, not a crib.
Sam's mother announces he will start nursery school. He associates "nursery" with nurses and fears he will have to give shots. On a visit, he vows not to play and not to try the giraffe-shaped slide, relenting only to go down it "just one time to be polite." At dinner that evening, he dominates the conversation with breathless enthusiasm, especially about his new friend Adam, who is constantly put in "Time Out" for rough play. He whispers the best news: "they don't give shots."
At the supermarket, Sam slips away from his mother's "No Candy" checkout line and quietly pockets a giant-sized pack of gum. On the way home, when his mother calls him "sweetie," Sam begins to sob and hands her the gum. They return to the supermarket, find the manager, apologize, and pay. Afterward, they throw the gum away, and Sam's good day resumes.
Sam wants a pet, but his father is allergic to dogs and cats. One evening, he finds an earthworm in his sandbox, names it King of Worms, and keeps it in a box of dirt hidden in his closet. When a pet show is announced at the public library, Sam enters. Prizes go to animals in quirky categories, but when the judges reach Sam's table, King of Worms has escaped. Sam receives a ribbon for "Most Invisible Pet" and is devastated. Anastasia consoles him, suggesting the worm escaped underground and headed home. When they dig near the sandbox, they find a worm, and Sam declares King of Worms beat them home.
On show-and-tell day at nursery school, Sam sneaks his father's pipe and lighter. He puts the pipe in his mouth and tries to operate the lighter, but his teacher, Mrs. Bennett, stops him immediately. Sam lies, claiming the pipe is his and that his whole family smokes. Mrs. Bennett redirects the situation into a health and safety lesson, and Sam enthusiastically tells the class never to play with lighters or matches.
Sam admires his friend Adam's punk hairstyle and decides to give himself one. Alone in the bathroom, he finds his father's beard-trimming scissors and begins snipping his curls. Twenty minutes later, the result is chunks of uneven hair and a bald spot. His mother stares in silence. Sam wails that he is "an ugly porkypine." She confesses a strong urge to spank him but suggests they try to laugh instead. The laughter starts forced but becomes genuine, growing until the whole family is howling together. A barber repairs the damage the next morning, and for four weeks Sam sports the most interesting punk hairdo in town.
Sam wants big muscles so he can be a "He-Man." Anastasia tells him muscles come from "pumping iron," so Sam retrieves his mother's clothes iron and a high-heeled pump, trying to combine them. He can only manage to "iron the pump," which accomplishes nothing. His mother reminds him that Popeye eats spinach, so Sam forces himself to eat cold leftovers. His father gently reveals that the spinach method only works for Popeye and admits he is "Mister Flabbo." Sam lovingly calls him "Good old Mr. Flabbo," and they agree to start exercising together.
After learning about secret codes from Anastasia, Sam visits his elderly next-door neighbor, Gertrude Stein, whom he calls "Gertrustein." She lives alone, bakes cookies almost every day, and reveals she knows Morse code from wartime. She teaches him all afternoon, telling him he has "a mind like a steel trap." That night, Sam asks his mother to turn off his Mickey Mouse night-light for the first time. In the dark, he aims his father's flashlight out his bedroom window and flashes the Morse code signal for "Desire to establish contact." After a pause, Gertrustein's flashlight blinks back: "Contact established." They exchange "Hi" and agree to flash this greeting every night.
Alone in his dark room, Sam flashes his own name in Morse code at the ceiling, the closet, his trucks, his books, and even a half-eaten egg salad sandwich hidden behind the curtains. "That's me," he thinks with satisfaction, and falls asleep.